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  • 1.
    Andersson, Claes-Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Synthesis and characterization of a ferrocene-linked bis-fullerene[60] dumbbell2012In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 41, no 8, p. 2374-2381Article in journal (Refereed)
    Abstract [en]

    A new [60]fullerene dumbbell consisting of two fulleropyrrolidines connected to a central ferrocene unit by amide linkages has been prepared and fully characterized by elemental analysis, 1H NMR, UV/Vis, fluorescence and mass spectrometry. The electrochemical properties as determined by cyclic voltammetry show ground state electronic communication between the ferrocene and the fullerene units. In addition, the preparaton of a ferrocene building block for an alternative linking approach is presented.

  • 2.
    Andersson, Matilda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Högström, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Urbonaite, Sigita
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Furlan, Andrej
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Deposition and characterization of magnetron sputtered amorphous Cr-C films2012In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 86, no 9, p. 1408-1416Article in journal (Refereed)
    Abstract [en]

    Thin films in the Cr-C system with carbon content of 25-85 at.% have been deposited using non-reactive DC magnetron sputtering from elemental targets. Analyses with X-ray diffraction and transmission electron microscopy confirm that the films are completely amorphous. Also, annealing experiment show that the films had not crystallized at 500 degrees C. Furthermore, X-ray spectroscopy and Raman spectroscopy show that the films consist of two phases, an amorphous CrCx phase and an amorphous carbon (a-C) phase. The presence of two amorphous phases is also supported by the electrochemical analysis, which shows that oxidation of both chromium and carbon contributes to the total current in the passive region. The relative amounts of these amorphous phases influence the film properties. Typically, lower carbon content with less a-C phase leads to harder films with higher Young's modulus and lower resistivity. The results also show that both films have lower currents in the passive region compared to the uncoated 316L steel substrate. Finally, our results were compared with literature data from both reactively and non-reactively sputtered chromium carbide films. The comparison reveals that non-reactive sputtering tend to favour the formation of amorphous films and also influence e.g. the sp(2)/sp(3) ratio of the a-C phase. 

  • 3.
    Asfaw, Habtom D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Maibach, Julia
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ångström, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Tai, Cheuk-Wai
    Bacsik, Zoltan
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Boosting the thermal stability of emulsion–templated polymers via sulfonation: an efficient synthetic route to hierarchically porous carbon foams2016In: ChemistrySelect, ISSN 2365-6549, Vol. 1, no 4, p. 784-792Article in journal (Refereed)
    Abstract [en]

    Hierarchically porous carbon foams with specific surface areas exceeding 600 m2 g−1 can be derived from polystyrene foams that are synthesized via water-in-oil emulsion templating. However, most styrene-based polymers lack strong crosslinks and are degraded to volatile products when heated above 400 oC. A common strategy employed to avert depolymerization is to introduce potential crosslinking sites such as sulfonic acids by sulfonating the polymers. This article unravels the thermal and chemical processes leading up to the conversion of sulfonated high internal phase emulsion polystyrenes (polyHIPEs) to sulfur containing carbon foams. During pyrolysis, the sulfonic acid groups (-SO3H) are transformed to sulfone (-C-SO2-C-) and then to thioether (-C−S-C-) crosslinks. These chemical transformations have been monitored using spectroscopic techniques: in situ IR, Raman, X-ray photoelectron and X-ray absorption near edge structure spectroscopy. Based on thermal analyses, the formation of thioether links is associated with increased thermal stability and thus a substantial decrease in volatilization of the polymers.

  • 4.
    Asfaw, Habtom Desta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Roberts, Matthew R.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Tai, Cheuk-Wai
    Stockholm University.
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. DTU.
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nanosized LiFePO4-decorated emulsion-templated carbon foam for 3D micro batteries: a study of structure and electrochemical performance2014In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 6, no 15, p. 8804-8813Article in journal (Refereed)
    Abstract [en]

    In this article, we report a novel 3D composite cathode fabricated from LiFePO4 nanoparticles deposited conformally on emulsion-templated carbon foam by a sol–gel method. The carbon foam is synthesized via a facile and scalable method which involves the carbonization of a high internal phase emulsion (polyHIPE) polymer template. Various techniques (XRD, SEM, TEM and electrochemical methods) are used to fully characterize the porous electrode and confirm the distribution and morphology of the cathode active material. The major benefits of the carbon foam used in our work are closely connected with its high surface area and the plenty of space suitable for sequential coating with battery components. After coating with a cathode material (LiFePO4nanoparticles), the 3D electrode presents a hierarchically structured electrode in which a porous layer of the cathode material is deposited on the rigid and bicontinuous carbon foam. The composite electrodes exhibit impressive cyclability and rate performance at different current densities affirming their importance as viable power sources in miniature devices. Footprint area capacities of 1.72 mA h cm−2 at 0.1 mA cm−2 (lowest rate) and 1.1 mA h cm−2 at 6 mA cm−2(highest rate) are obtained when the cells are cycled in the range 2.8 to 4.0 V vs. lithium.

  • 5.
    Asfaw, Habtom Desta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Tai, Cheuk-Wai
    Stockholm Univ, Arrhenius Lab, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Over-Stoichiometric NbO2 Nanoparticles for a High Energy and Power Density Lithium Microbattery2017In: CHEMNANOMAT, ISSN 2199-692X, Vol. 3, no 9, p. 646-655Article in journal (Refereed)
    Abstract [en]

    Effective utilization of active materials in microbatteries can be enhanced by rational design of the electrodes. There is an increasing trend of using 3D electrodes that are coated in nanosized active materials to boost both energy and power densities. This article focuses on the fabrication of 3D electrodes based on monolithic carbon foams coated in over-stoichiometric NbO2 nanoparticles. The electrodes exhibit remarkable energy and power densities at various current densities when tested in lithium microbatteries. An areal capacity of around 0.7mAhcm(-2) and energy density up to 45mWhcm(-3) have been achieved. More than half of the areal capacity can be accessed at a current density of about 11mAcm(-2), with the corresponding energy and power densities being 21mWhcm(-3) and 1349mWcm(-3). These values are comparable to those of microsupercapacitors containing carbon and MnO2 nanomaterials. Furthermore, the electrochemical reversibility improves progressively upon cycling along with substantial increase in the charge transfer kinetics of the electrode. Based on impedance analyses almost a fourfold decrease in the charge transfer resistance has been observed over 25 cycles. Such enhancement of the electronic properties of NbO2 can account for the high electrochemical rate performance of the 3D electrodes.

  • 6.
    Baglien, Ida
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. strukturkemi.
    Nyholm, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Edström, Kristina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. strukturkemi.
    The Influence on the SEI of Different Cell Designs2006In: Presented at the International Meeting on Lithium Batteries (IMLB2006) meeting in Biarritz, France, June 18-23, 2006Conference paper (Refereed)
  • 7.
    Baglien, Ida
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. strukturkemi.
    Nyholm, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. oorganisk kemi.
    Hedlund, M
    Rensmo, H
    Siegbahn, H
    Edström, Kristina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. strukturkemi.
    Characterisation of the SEI formed on Graphite using Synchrotron PES2005In: presented at the 208th Electrochemical Society Meeting, Los Angeles, 16-21 October, 2005Conference paper (Refereed)
  • 8.
    Bryngelsson, Hanna
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. strukturkemi.
    Eskhult, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Nyholm, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Edström, Kristina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. strukturkemi.
    Electrodeposited Nano-sized Thin Films of Sb and Sb2O3 as Anode Materials in Li-ion Batteries2006In: Presented at the 57th Annual Meeting of the International Society of Electrochemistry, Edinburgh, August 27 - September 1, 2006Conference paper (Refereed)
  • 9.
    Bryngelsson, Hanna
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. strukturkemi.
    Eskhult, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Nyholm, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Edström, Kristina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. strukturkemi.
    The role of the Oxide in Electrodeposited Nano-sized Thin Films of Sb2006In: Presented at the International Meeting on Lithium Batteries (IMLB2006) meeting in Biarritz, France, June 18-23, 2006Conference paper (Refereed)
  • 10.
    Böhme, Solveig
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Electrochemical behavior of tin(IV) oxide electrodes in lithium-ion batteries at elevated temperaturesManuscript (preprint) (Other academic)
  • 11.
    Böhme, Solveig
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    On the electrochemistry of tin oxide coated tin electrodes in lithium-ion batteries2015In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 179, p. 482-494Article in journal (Refereed)
    Abstract [en]

    As tin based electrodes are of significant interest in the development of improved lithium-ion batteries it is important to understand the associated electrochemical reactions. In this work it is shown that the electrochemical behavior of SnO2 coated tin electrodes can be described based on the SnO2 and SnO conversion reactions, the lithium tin alloy formation and the oxidation of tin generating SnF2. The CV, XPS and SEM data, obtained for electrodeposited tin crystals on gold substrates, demonstrates that the capacity loss often observed for SnO2 is caused by the reformed SnO2 layer serving as a passivating layer protecting the remaining tin. Capacities corresponding up to about 80 % of the initial SnO2 capacity could, however, be obtained by cycling to 3.5 V vs. Li+/Li. It is also shown that the oxidation of the lithium tin alloy is hindered by the rate of the diffusion of lithium through a layer of tin with increasing thickness and that the irreversible oxidation of tin to SnF2 at potentials larger than 2.8 V vs. Li+/Li is due to the fact that SnF2 is formed below the SnO2 layer. This improved electrochemical understanding of the SnO2/Sn system should be valuable in the development of tin based electrodes for lithium-ion batteries.

  • 12.
    Böhme, Solveig
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Overlapping and rate controlling electrochemical reactions for tin(IV) oxide electrodes in lithiu-ion batteries2017In: Journal of Electroanalytical Chemistry, ISSN 0022-0728, E-ISSN 1873-2569, Vol. 797, p. 47-60Article in journal (Refereed)
    Abstract [en]

    The results of this extensive electrochemical study of the electrochemical reactions of SnO2 electrodes in lithium-ion batteries demonstrate that the different reduction and oxidation reactions overlap significantly during the cycling and that the rates of the redox reactions are limited by the mass transport through the layers of oxidation or reduction products formed on the electrodes. The experiments, which were carried out in the absence and presence of the lithium alloy reactions, show that the capacity losses seen on the first cycles mainly can be explained by an incomplete oxidation of the lithium tin alloy and an incomplete reformation of SnO2. The latter can be explained by the formation of thin tin oxide layers (i.e., SnO and SnO2), protecting the remaining tin, as the oxidation current then becomes limited by the Li+ diffusion rate though these layers. The results, also show that the first cycle SnO2 reduction was incomplete for the about 20 μm thick electrodes containing 1 to 6 μm large SnO2 particles. This can be ascribed to the formation of a layer of tin and Li2O (protecting the remaining SnO2) during the reduction process. Although the regeneration of the SnO2 always was slower than the reduction of the SnO2, the results clearly show that the SnO2 conversion reaction is far from irreversible, particularly at low scan rates and increased temperatures. Electrochemical cycling at 60 °C hence gave rise to increased capacities, but also a faster capacity loss, compared to at room temperature. These new findings indicate that a full utilization of SnO2 based electrodes at a given cycling rate only can be reached with sufficiently small particles since the allowed particle size is given by the time available for the mass transport through the formed surface layers. The present results consequently provide important insights into the phenomena limiting the use of SnO2 electrodes in lithium-ion batteries.

  • 13.
    Böhme, Solveig
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Kerner, Manfred
    Department of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Scheers, Johan
    Department of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Johansson, Patrik
    Department of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Elevated Temperature Lithium-Ion Batteries Containing SnO2 Electrodes and LiTFSI-Pip14TFSI Ionic Liquid Electrolyte2017In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 4, p. A701-A708Article in journal (Refereed)
    Abstract [en]

    The performance of lithium-ion batteries (LIBs) comprising SnO2 electrodes and an ionic liquid (IL) based electrolyte, i.e., 0.5 MLiTFSI in Pip14TFSI, has been studied at room temperature (i.e., 22◦C) and 80◦C. While the high viscosity and low conductivity ofthe electrolyte resulted in high overpotentials and low capacities at room temperature, the SnO2 performance at 80◦C was found to beanalogous to that seen at room temperature using a standard LP40 electrolyte (i.e., 1MLiPF6 dissolved in 1:1 ethylene carbonate anddiethyl carbonate). Significant reduction of the IL was, however, found at 80◦C, which resulted in low coulombic efficiencies duringthe first 20 cycles, most likely due to a growing SEI layer and the formation of soluble IL reduction products. X-ray photoelectronspectroscopy studies of the cycled SnO2 electrodes indicated the presence of an at least 10 nm thick solid electrolyte interphase (SEI)layer composed of inorganic components such as lithium fluoride, sulfates, and nitrides as well as organic species containing C-H,C-F and C-N bonds.

  • 14.
    Böhme, Solveig
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Philippe, Bertrand
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Photoelectron Spectroscopic Evidence for Overlapping Redox Reactions for SnO2 Electrodes in Lithium-Ion Batteries2017In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 9, p. 4924-4936Article in journal (Refereed)
    Abstract [en]

    In-house and synchrotron-based photoelectron spectroscopy (XPSand HAXPES) evidence is presented for an overlap between the conversion andalloying reaction during the cycling of SnO2 electrodes in lithium-ion batteries(LIBs). This overlap resulted in an incomplete initial reduction of the SnO2 as wellas the inability to regenerate the reduced SnO2 on the subsequent oxidative scan.The XPS and HAXPES results clearly show that the SnO2 conversion reactionoverlaps with the formation of the lithium tin alloy and that the conversion reactiongives rise to the formation of a passivating Sn layer on the SnO2 particles. The latterlayer renders the conversion reaction incomplete and enables lithium tin alloy toform on the surface of the particles still containing a core of SnO2. The results alsoshow that the reoxidation of the lithium tin alloy is incomplete when the formationof tin oxide starts. It is proposed that the rates of the electrochemical reactions andhence the capacity of SnO2-based electrodes are limited by the lithium masstransport rate through the formed layers of the reduction and oxidations products.In addition, it is shown that a solid electrolyte interphase (SEI) layer is continuously formed at potentials lower than about 1.2 VLi+/Li during the first scan and that a part of the SEI dissolves on the subsequent oxidative scan. While the SEI was found tocontain both organic and inorganic species, the former were mainly located at the SEI surface while the inorganic species werefound deeper within the SEI. The results also indicate that the SEI dissolution process predominantly involves the organic SEIcomponents.

  • 15.
    Carlsson, Daniel O
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ferraz, Natalia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Fellström, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Renal Medicine.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Towards blood purification applications of polypyrrole and cellulose nanocomposites2013Conference paper (Refereed)
  • 16.
    Carlsson, Daniel O
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ferraz, Natalia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hong, Jaan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Clinical Immunology.
    Larsson, Rolf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Clinical Immunology.
    Fellström, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Forensic Medicine.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Conducting Nanocellulose Polypyrrole Membranes Intended for Hemodialysis2012In: European Cells and Materials, ISSN 1473-2262, E-ISSN 1473-2262, Vol. 23, no Suppl 5, p. 32-32Article in journal (Refereed)
  • 17.
    Carlsson, Daniel O
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ferraz, Natalie
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hong, J
    Larsson, R
    Fellström, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Renal Medicine.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Conduting nanocellulose polypyrrole membranes intended for hemodialysis2012Conference paper (Refereed)
  • 18.
    Carlsson, Daniel O.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Cooxidant-free TEMPO-mediated oxidation of highly crystalline nanocellulose in water2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 94, p. 52289-52298Article in journal (Refereed)
    Abstract [en]

    Selective oxidation of C6 hydroxyls to carboxyls through 2,2,6,6,-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, where the oxidizing species (TEMPO+) is generated by cooxidants, such as NaBrO, NaClO or NaClO2, has become a popular way to modify the surfaces of nanocellulose fibrils in aqueous solutions. Employing highly crystalline nanocellulose from Cladophora sp. algae we demonstrate that the same degree of oxidation (D.O.) can be achieved within approximately the same time by replacing the cooxidants with electrogeneration of TEMPO+ in a bulk electrolysis setup. The D.O. is controlled by the oxidation time and the maximum D.O. achieved (D.O. 9.8%, 0.60 mmol g-1 of carboxylic acids and 0 mmol g-1 aldehydes) corresponds to complete oxidation of the surface-confined C6. This shows that TEMPO+ is not sterically hindered from completely oxidizing the fibril surface of Cladophora nanocellulose, in contrast to earlier hypotheses that were based on results with wood-derived nanocellulose. The oxidation does not significantly affect the morphology, the specific surface area (>115 m2 g-1) or the pore characteristics of the water-insoluble fibrous particles that were obtained after drying, but depolymerization corresponding to [similar]20% was observed. For extensive oxidation times, the product recovery of water-insoluble fibrils decreased significantly while significant amounts of charge passed through the system. This could indicate that the oxidation proceeds beyond the fibril surface, in contrast to the current view that TEMPO-mediated oxidation is confined only to the surface.

  • 19.
    Carlsson, Daniel O
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Cooxidant-free TEMPO-mediated oxidation of highly crystalline Cladophora nanocellulose2015Conference paper (Refereed)
  • 20.
    Carlsson, Daniel O
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Electrochemical TEMPO-mediated Oxidation of Highly Crystalline Nanocellulose in Water2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, p. 52289-52298Article in journal (Refereed)
  • 21.
    Carlsson, Daniel O.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Stability of Polypyrrole Cellulose Composites in Aqueous Solutions and Under Ambient Conditions.2011In: MRS Spring meeting 2011, 2011Conference paper (Refereed)
  • 22.
    Carlsson, Daniel O.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Tailoring porosities and electrochemical properties of composites composed of microfibrillated cellulose and polypyrrole2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 17, p. 8489-8497Article in journal (Refereed)
    Abstract [en]

    Composites of polypyrrole and nanocellulose (PPy/nanocellulose) have a high potential as electrodes in energy-storage devices and as membranes for electrochemically controlled ion-exchange systems. In the present work, it is demonstrated that such composites with 42-72% porosity can be produced by using microfibrillated cellulose (MFC) prepared through enzymatic pretreatment or carboxymethylation, or by using different amounts of MFC in the composite synthesis. Together with previous work, this shows that the porosity of PPy/nanocellulose composites can be tailored from 30 to 98% with increments of similar to 10%. Employing the full porosity range of the composites, it is demonstrated that the electrochemical oxidation rate of the materials depends on their porosity due to limitations in the counter ion diffusion process. By tailoring the porosities of PPy/nanocellulose composites, the electrochemical properties can consequently be controlled. The latter provides new possibilities for the manufacturing of electrochemically controlled ion-extraction and energy storage devices with optimized volumetric energy and power densities.

  • 23.
    Carlsson, Daniel O
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyström, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ferraz, Natalia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Development of nanocellulose/polypyrrole composites towards blood purification2012In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 44, p. 733-736Article in journal (Refereed)
  • 24.
    Carlsson, Daniel O
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyström, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ferraz, Natalia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Shou, Qi
    Berglund, Lars A
    Fellström, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Development of Nanocellulose/Polypyrrole Composites Towards Blood Purification2012In: Euromembrane 2012, Queen Elizabeth II Conference Centre, London, UK, 23-27 September 2012, 2012Conference paper (Refereed)
  • 25.
    Carlsson, Daniel O
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyström, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Olsson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Stability of Cladophora Cellulose/Polypyrrole Nanocomposites in Aqueous solutions2010Conference paper (Refereed)
  • 26.
    Carlsson, Daniel O
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyström, Gustav
    KTH, Wallenberg Wood Science Center, Stockholm.
    Zhou, Qi
    KTH, Dept of Fibre & Polymer Technology, Stockholm.
    Berglund, Lars A.
    KTH, Dept of Fibre & Polymer Technology, Stockholm.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Electroactive nanofibrillated cellulose aerogel composites with tunable structural and electrochemical properties2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 36, p. 19014-19024Article in journal (Refereed)
  • 27.
    Carlsson, Daniel O.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    A Comparative Study of the Effects of Rinsing and Aging of Polypyrrole/Nanocellulose Composites on Their Electrochemical Properties2013In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 117, no 14, p. 3900-3910Article in journal (Refereed)
    Abstract [en]

    The effects of polymerization conditions, rinsing, and storage on composites composed of polypyrrole (PPy) and Cladophora nanocellulose in terms of purity, chemical composition, conductivity, and electroactivity were investigated using conductivity measurements, cyclic voltammetry, FTIR-ATR, XPS, and ICP-AES. A clear correlation between rinsing volume and PPy degradation was found using water- or NaCl-rinsing solutions as evidenced by conductivity and electroactivity losses. It was further found, through FTIR-ATR as well as XPS-measurements, that this degradation was caused by incorporation of hydroxyl groups in the PPy-layer. The extent of degradation correlated with a shift in the FTIR-ATR peak around 1300 cm(-1), showing that FTIR-ATR may be used as a quick diagnostic tool to evaluate the extent of degradation. By the use of acidic rinsing solution, this degradation effect was eliminated and resulted in superior samples in terms of both conductivity and electroactivity and also in a more efficient removal of reactants. Upon ambient storage, over a period of 200 days, a gradual decrease in conductivity was found for initially highly conductive samples. The electroactivity, on the other hand, was relatively unaffected by storage, showing that conductivity measurements alone are ineffective to determine the degree of polymer degradation if the water content is not controlled. Also, FTIR-ATR measurements indicated that the oxidation state did not change to any large extent upon storage and that only minor degradation of PPy occurred. The results presented herein thus offer valuable guidelines on how to develop simple and reliable postsynthesis treatments of conducting polymer paper composites with performance fulfilling requirements on stability, electroactivity, and purity in applications such as environmentally friendly energy storage devices and biomedical applications.

  • 28.
    Cheah, Seng Kian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Perre, Emilie
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Rooth, Mårten
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Fondell, Mattis
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Hårsta, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Lu, Jun
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microstructure Laboratory.
    Simon, Patrice
    CIRIMAT, Université Paul Sabatier, Toulouse, France.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Self-Supported Three-Dimensional Nanoelectrodes for Microbattery Applications2009In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 9, no 9, p. 3230-3233Article in journal (Refereed)
    Abstract [en]

    A nanostructured three-dimensional (3D) microbattery has been produced and cycled in a Li-ion battery. It consists of a current collector of aluminum nanorods, a uniform layer of 17 nm TiO2 covering the nanorods made using ALD, an electrolyte and metallic lithium counter electrode. The battery is electrochemically cycled more than 50 times. The increase in total capacity is 10 times when using a 3D architechture compared to a 2D system for the same footprint area.

  • 29.
    Chen, Si
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jokilaakso, Nima
    School of Biotechnology, KTH, Stockholm.
    Karlström, Amelie Eriksson
    School of Biotechnology, KTH, Stockholm.
    Linnros, Jan
    School of Information and Communication Technology, KTH, Stockholm.
    Smith, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Current Instability for Silicon Nanowire Field-Effect Sensors Operating in Electrolyte with Platinum Gate Electrodes2011In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 14, no 7, p. J34-J37Article in journal (Refereed)
    Abstract [en]

    Current instability is observed for silicon nanowire field-effect transistors operating in electrolytes with Pt gate electrodes. A comparative study involving an Ag/AgCl-reference gate electrode reveals that the effect results from a drift in the potential at the Pt-electrode/electrolyte interface. In a phosphate buffer saline of pH 7.4, the stabilization of the potential of the Pt electrode was found to require approximately 1000 s. A concurrent potential drift, with a comparable time constant, occurring at the electrolyte/oxidized-nanowire interface rendered a complex device current response which complicated the interpretation of the results.

  • 30.
    Ciosek Högström, Katarzyna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Malmgren, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Hahlin, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Gorgoi, Mihaela
    Helmholtz Zentrum Berlin Germany.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    The Buried Carbon/Solid Electrolyte Interphase in Li-ion Batteries Studied by Hard X-ray Photoelectron Spectroscopy2014In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 138, p. 430-436Article in journal (Refereed)
  • 31.
    Co, Michelle
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Zettersten, Camilia
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Sjöberg, Per J.R
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Turner, Charlotta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Degradation effects in the extraction of antioxidants from birch bark using water at elevated temperature and pressure2012In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 716, p. 40-48Article in journal (Refereed)
    Abstract [en]

    Experiments with birch bark samples have been carried to enable a distinction between extraction and degradation effects during pressurised hot water extraction. Two samples, E80 and El 80, contained birch bark extracts obtained after extraction at 80 and 180 degrees C for up to 45 min, respectively. Two other samples, P80 and P180, were only extracted for 5 min at the two temperatures and were thereafter filtered and hydrothermally treated at 80 and 180 degrees C, respectively. During the latter treatment, samples were collected at different times to assess the stability of the extracted compounds. An offline DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, as well as a high performance liquid chromatographic separation coupled to an electrochemical detector, were used to determine the antioxidant capacity of the processed samples. The results obtained with the different techniques were compared to assess the yield of the extraction and degradation processes. In addition, an online hyphenated system comprising high performance liquid chromatography coupled to diode-array; electrochemical; and tandem mass spectrometric detection (HPLC-DAD-ECD-MS/MS) was used to study the compositions of the extracts in more detail. The results for the samples processed at 80 degrees C showed that the extraction reached a steady-state already after 5 min, and that the extracted compounds were stable throughout the entire extraction process. Processing at 180 degrees C, on the other hand, gave rise to partly degraded extracts with a multitude of peaks in both the diode array and electrochemical detectors, and a higher antioxidant capacity compared to for the extracts obtained at 80 degrees C. It is concluded that HPLC-DAD-ECD is a more appropriate technique for the determination of antioxidants than the DPPH assay. The mass spectrometric results indicate that one of the extracted antioxidants, catechin, was isomerised to its diastereoisomers; (+)-catechin, (-)-catechin, (+)-epicatechin, and (-)-epicatechin.

     

  • 32.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Electrodeposition as a Tool for 3D Microbattery Fabrication2011In: The Electrochemical Society interface, ISSN 1064-8208, Vol. 20, no 2, p. 41-46Article in journal (Refereed)
  • 33. Eriksson, A
    et al.
    Nyholm, L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    A comparative study of the oxidation of 3-, 4- and 5-aminosalicylic acids at glassy carbon electrodes1998In: ELECTROANALYSIS, ISSN 1040-0397, Vol. 10, no 3, p. 198-203Article in journal (Refereed)
    Abstract [en]

    The oxidation behavior of 3-aminosalicylic acid (3-ASA), 4-aminosalicylic acid (4-ASA) and 5-aminosalicyclic acid (5-ASA), the active part of the drugs Sulphasalazine and Dipentum for the treatment of ulcerative colitis, has been compared. The redox beha

  • 34. Eriksson, Kristofer
    et al.
    Johansson, LarsErik
    Göthelid, Emmanuelle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Oscarsson, Sven
    Manufacturing of anisotropic particles by site specific oxidation of thiols2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 16, p. 7681-7683Article in journal (Refereed)
    Abstract [en]

    A novel method for the manufacturing of functional anisotropic particles based on an inexpensive and straightforward electrochemical approach is presented. The method enables large-scale manufacturing of anisotropic particles as well as fabrication of multifunctional beads which may be used in the design of barcodes for multiplex diagnostics.

  • 35. Eriksson, Kristofer
    et al.
    Palmgren, Pål
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Oscarsson, Sven
    Electrochemical Synthesis of Gold and Protein Gradients on Particle Surfaces2012In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 28, no 28, p. 10318-10323Article in journal (Refereed)
    Abstract [en]

    A straightforward, versatile approach to the production of protein gradients on planar and spherical particle surfaces is described. The method is based on the spatially controlled oxidation of thiolated surfaces by Au(III) ions generated via the electrochemical oxidation of a gold electrode in a phosphate-buffered saline solution (10 mM PBS, pH 7.2, 150 mM NaCl). Because the gold electrode is in direct contact with the thiolated surfaces, the released Au(III) ions, which are present as Au(III) chloride complexes, give rise to the formation of a surface gradient of Au(I)-thiolate complexes depending on the local redox potential given by the local Au(III) concentration. As is shown on the basis of the use of X-ray photoelectron spectroscopy and fluorescently labeled proteins, the Au(I)-thiolate complexes can subsequently be functionalized with thiolated proteins, yielding surface density protein gradients on micrometer-sized nonconducting polymer beads as well as linear Au(I)-thiolate gradients on planar silicon surfaces.

  • 36. Eriksson, Kristofer
    et al.
    Verho, Oscar
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Oscarsson, Sven
    Backvall, Jan-E.
    Dispersed Gold Nanoparticles Supported in the Pores of Siliceous Mesocellular Foam: A Catalyst for Cycloisomerization of Alkynoic Acids to gamma-Alkylidene Lactones2015In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 10, p. 2250-2255Article in journal (Refereed)
    Abstract [en]

    A versatile approach for the production of dispersed thiol-stabilized gold nanoparticles in the pores of siliceous mesocellular foam (MCF) is described. The reported method is based on an electrochemical oxidation of a gold surface generating oxidative Au-III species, which give rise to a surface-confined redox reaction yielding MCF-supported Au-I thiolates. By reducing the corresponding Au-I-S-MCF species with sodium borohydride, thiol-stabilized gold nanoparticles in the size range of 1-8 nm were obtained as determined by transmission electron microscopy. Elemental analysis indicated an Au loading of 3% (w/w) on the MCF. The surface-confined Au nanoparticles were used to catalyze the cycloisomerization of alkynoic acids to the corresponding -alkylidene lactones in high efficiency and complete 5-exo-dig selectivity under mild reaction conditions.

  • 37.
    Eskhult, Jonas
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Herranen, Merja
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Nyholm, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    On the Origin of the Spontaneous Potential Oscillations Observed during Galvanostatic Deposition of Layers of Cu and Cu2O in Alkaline Citrate Solutions2006In: Presented at the 57th Annual Meeting of the International Society of Electrochemistry, Edinburgh, August 27 - September 1, 2006Conference paper (Refereed)
  • 38.
    Eskhult, Jonas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Herranen, Merja
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    On the origin of the spontaneous potential oscillations observed during galvanostatic deposition of layers of Cu and Cu2O in alkaline citrate solutions2006In: Journal of Electroanalytical Chemistry, ISSN 0022-0728, E-ISSN 1873-2569, Vol. 594, no 1, p. 35-49Article in journal (Refereed)
    Abstract [en]

    Potential oscillations are demonstrated under reducing galvanostatic conditions in alkaline solutions of 0.4 M Cu(II) and 1.2 M citrate at elevated temperatures. The oscillations, which give rise to the deposition of layers of Cu and Cu2O, as verified by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) as well as Raman measurements, originate from local modulations of the pH in the vicinity of the working electrode. A reaction scheme for the oscillations is presented based on the model previously proposed by Leopold et al. [J. Electroanal. Chem., 547 (2003) 45-52] for the Cu(II)-lactate system. It is shown that the oscillations are due to the fact that the rate of the electrodeposition Of Cu2O is modulated by the local pH variations. This causes this reaction to be switched on and off as the local pH increases and decreases, respectively. In analogy with the Cu(II)-lactate case, a local pH increase is obtained during the deposition of copper from the [Cu(2)H(-2)Cit(2)](4-) complex ([Cu(2)H(-2)Cit(2)](4-) + 4e(-) + 2H(2)O = 2Cu + 2[Cit](3-) + 2OH(-)) predominating in the solution. This increase stems from the protonation of the liberated citrate. As a result of this, electrodeposition Of Cu2O ([Cu(2)H(-2)Cit(2)](4-) + 2e(-) + H2O = Cu2O + 2[Cit](3-)) becomes possible at the rate required by the constant current. However, electrochemical quartz crystal microbalance (EQCM) data clearly show that the onset of this reaction is accompanied by an electroless deposition of Cu2O. This reaction, which under oscillating conditions mainly involves a comproportionation reaction ([Cu(2)H(-2)Cit(2),](4-) + 2Cu + 2OH(-) = 2Cu(2)O + 2[Cit](3-)), can give rise to Cu2O deposition at current efficiencies much larger than 100%. As a result of the combined electroless deposition and electrodeposition Of Cu2O, the local pH decreases rapidly, mainly due to the comproportionation reaction. When the local pH drops, the electrodeposition Of Cu2O becomes unable to sustain the current and the potential shifts negatively. This causes the onset of the reduction of the previously deposited Cu2O (i.e. Cu2O + 2e(-) + H2O = 2Cu + 2OH(-)). The EQCM and XRD results, however, clearly show that this reduction is incomplete during the oscillating conditions. This finding, which explains the presence of both copper and Cu2O in the deposits, is ascribed to the formation of a growing layer of copper on top of the remaining Cu2O. It is shown that the extent of the Cu2O reduction (and thus the amount Of Cu2O in the obtained deposits) depends on the Cu(II) concentration in the solution. Finally, the oscillation cycle is completed by a gradual replacement of the reduction Of Cu2O by the reduction of the [Cu(2)H(-2)Cit(2)](4-) complex, which causes the local pH to increase again. The proposed model is discussed in detail with particular emphasis on the reactions taking place in the region of the oscillation potential peak.The requirements for the attainment of oscillations under quiescent and forced convection conditions are discussed as well as the applicability of the model with respect to other Cu(II)complx systems.

  • 39.
    Eskhult, Jonas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Pulsed galvanostatic and potentiostatic electrodeposition of Cu and Cu2O nanolayers from alkaline Cu(II)-citrate solutions2008In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 155, no 2, p. D115-D122Article in journal (Refereed)
    Abstract [en]

    Nanolayers of Cu and Cu2O with a wide range of layer thicknesses have been produced using pulsed galvanostatic and potentiostatic electrodeposition from alkaline Cu(II)-citrate solutions. The thicknesses of the individual Cu and Cu2O layers can be independently controlled and the composition of the multilayered materials, which also were studied using electrochemical quartz crystal microbalance, X-ray diffraction, and scanning electron microscopy, can be varied from pure Cu to pure Cu2O by varying the current density or the deposition potential. It is shown that some of the deposited Cu2O is reduced during the subsequent copper deposition step and that the influence of this effect depends on the Cu (II) concentration, the Cu2O microstructure, and the deposition mode. Additional Cu2O deposition is demonstrated to take place after the copper deposition step due to comproportionation and precipitation of Cu2O. This effect facilitates electrodeposition of Cu2O on Cu. Deposition of Cu on the Cu2O layer formed by comproportionation and precipitation was likewise found to be more straightforward than on electrodeposited Cu2O. Well-defined nanolayered Cu/Cu2O materials are generally best manufactured using pulsed galvanostatic techniques because a much larger fraction of the Cu2O was found to be reduced during the subsequent Cu deposition pulse in pulsed potentiostatic depositions.

  • 40.
    Ferraz, Natalia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Carlsson, Daniel O.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hong, Jaan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Clinical Immunology.
    Larsson, Rolf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Clinical Immunology.
    Fellström, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Renal Medicine.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification2012In: Journal of the Royal Society Interface, ISSN 1742-5689, E-ISSN 1742-5662, Vol. 9, no 73, p. 1943-1955Article in journal (Refereed)
    Abstract [en]

    Composites of nanocellulose and the conductive polymer polypyrrole (PPy) are presented as candidates for a new generation of haemodialysis membranes. The composites may combine active ion exchange with passive ultrafiltration, and the large surface area (about 80 m2 g−1) could potentially provide compact dialysers. Herein, the haemocompatibility of the novel membranes and the feasibility of effectively removing small uraemic toxins by potential-controlled ion exchange were studied. The thrombogenic properties of the composites were improved by applying a stable heparin coating. In terms of platelet adhesion and thrombin generation, the composites were comparable with haemocompatible polymer polysulphone, and regarding complement activation, the composites were more biocompatible than commercially available membranes. It was possible to extract phosphate and oxalate ions from solutions with physiological pH and the same tonicity as that of the blood. The exchange capacity of the materials was found to be 600 ± 26 and 706 ± 31 μmol g−1 in a 0.1 M solution (pH 7.4) and in an isotonic solution of phosphate, respectively. The corresponding values with oxalate were 523 ± 5 in a 0.1 M solution (pH 7.4) and 610 ± 1 μmol g−1 in an isotonic solution. The heparinized PPy–cellulose composite is consequently a promising haemodialysis material, with respect to both potential-controlled extraction of small uraemic toxins and haemocompatibility.

  • 41.
    Ferraz, Natalia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Carlsson, Daniel O
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hong, Jaan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Clinical Immunology.
    Larsson, Rolf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Clinical Immunology.
    Fellström, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hemocompatibility of Nanocellulose Polypyrrole Membranes Intended for Hemodialysis2012In: 9th World Biomaterials Congress, June 1-5, 2012, Chengdu, China, 2012Conference paper (Refereed)
  • 42.
    Ferraz, Natalia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Fellström, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Pradhan, Sulena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    In vitro and in vivo toxicity of rinsed and aged nanocellulose-polypyrrole composites2012In: Journal of Biomedical Materials Research. Part A, ISSN 1549-3296, E-ISSN 1552-4965, Vol. 100A, no 8, p. 2128-2138Article in journal (Refereed)
    Abstract [en]

    Novel composites of nanocellulose and the conducting polymer polypyrrole (PPy) are herein suggested as potential candidates for active ion-extraction membranes in electrochemically controlled hemodialysis. This work has defined processing parameters to obtain a biocompatible nanocellulose-PPy composite and for the first time, the effect of the composite ageing on cell viability has been studied.

    The influence of rinsing and extraction process steps, as well as ageing under different conditions (i.e. in air, at –20 ˚C and in argon), on the electroactivity and cytotoxicity of a PPy-nanocellulose composite has been investigated. The biocompatibility evaluation was based on indirect toxicity assays with fibroblasts and monocyte cell lines and an acute toxicity test in mice, while the electroactivity was evaluated by cyclic voltammetry experiments.

    The as-prepared composite did not induce any cytotoxic response in vitro or in vivo. Extensive rinsing and 48 hour incubation in biological buffer previous to the preparation of the culture medium extracts were, however, necessary to obtain a non-cytotoxic composite. The as-prepared composite was also found to exhibit acceptable electrochemical performance, which was retained upon 4 weeks storage in argon atmosphere.  It was shown that ageing of the composite had a negative effect on biocompatibility, regardless of the storage condition. Thus, to allow for long time storage of electroactive nanocellulose-PPy hemodialysis membranes, the degradation of PPy upon storage must be controlled. The present results show that the biocompatibility of PPy composites depends on the rinsing and pre-treatment of the composite material as well as the aging of the material.

  • 43.
    Forsberg, Pontus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Jorge, Eleonora de Oliveira
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Fabrication of boron doped diamond microband electrodes for electrochemical detection in a microfluidic channel2011In: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 20, no 8, p. 1121-1124Article in journal (Refereed)
    Abstract [en]

    The manufacturing and electrochemical characterisation of an array of 20 boron doped nanocrystalline diamond (BNCD) microband electrodes for use in a poly(dimethylsiloxane) (PDMS) based microfluidic system are described. The electrodes were fabricated by plasma etching of a silicon oxide- and BNCD thin film coated silicon wafer and the resulting surface structured silicon wafer was subsequently bonded to the PDMS so that the BNCD microband electrodes were located within the PDMS microchannel. The electrochemical performance of the BNCD electrodes was studied and the electrodes were found to exhibit significantly better stability than previously employed gold microband arrays.

  • 44.
    Fredriksson, Wendy
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Petrini, Daniel
    Erasteel Kloster AB, Box 100, Söderfors SE-815 82, Sweden.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Björefors, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Corrosion Resistances and Passivation of Powder Metallurgical and Conventionally Cast 316L and 2205 Stainless Steels2013In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 67, p. 268-280Article in journal (Refereed)
    Abstract [en]

    The corrosion resistances and passivation of austenitic 316L and duplex 2205 powder metallurgical (P/M) steels, produced by employing gas atomizing and hot isostatic pressing (HIP), have been compared with those of their conventional cast and forged counterparts. The P/M 316L steel is shown to have a significantly higher pitting corrosion resistance than the conventional 316L steel in 0.5 M HCl. Since the chemical composition and the total amount of inclusions were analogous for the two steels, the effect is ascribed to the finer grained microstructure for the P/M 316L steel yielding a better passive layer. This is supported by photoelectron spectroscopy data demonstrating differences between the thickness and composition of the passive layers for the two 316 L steels. Differences in the passivation process were also found for the different steels as three mixed potentials were observed in the polarization curves for the P/M and conventional 316L steels whereas only one mixed potential at about +0.7 V vs. Ag/AgCl was observed for the two duplex steels in 0.5 M HCl. The results indicate that discussions of the shapes of polarization curves and mixed potentials should be based on the anodic and cathodic partial currents, including the reduction of oxygen. HIP:ed P/M steels are clearly well-suited for applications requiring high pitting corrosion resistances.

  • 45.
    Högström, Jonas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Andersson, Matilda
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Björefors, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    On the evaluation of corrosion resistances of amorphous chromium carbide thin-films2014In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 122, no SI, p. 224-233Article in journal (Refereed)
    Abstract [en]

    The possibilities of evaluating the corrosion resistance of amorphous chromium carbide (Cr-C) films containing nanometre-sized carbide grains embedded in an amorphous carbon matrix on the basis of polarization curves, voltammograms and the oxidation charge have been studied for Cr-C films with different carbon concentrations. The films, which were manufactured by non-reactive directcurrent magnetron sputtering, were studied in 1.0 mM H2SO4 at both 22 °C and 80 °C, and with scanning electron microscopy and X-ray photoelectron spectroscopy prior to and after the electrochemical experiments. It is demonstrated that the oxidation of these Cr-C films gives rise to a surface composed of Cr2O3 and partially oxidized carbon and that the non-corroding oxidation current due to the carbon oxidation increases with increasing carbon concentration in the films as well as with the electrolyte temperature. Since the oxidation current is composed of contributions from both Cr-C and carbon oxidation it is not straightforward to evaluate the corrosion resistances of these films based on the current in the passive region, the mixed potential (i.e., the corrosion potential) or the open circuit potential. The present results in fact indicate that Cr-C films with high carbon concentrations may have better corrosion resistances than the corresponding films with lower carbon concentrations although larger currents in the passive region can be seen in polarization curves.

  • 46.
    Högström, Jonas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Fredriksson, Wendy
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Björefors, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Olsson, Claes-O. A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Cation profiling of passive films on stainless steel formed in sulphuric and acetic acid by deconvolution of angle-resolved X-ray photoelectron spectra2013In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 284, p. 700-714Article in journal (Refereed)
    Abstract [en]

    An approach for determining depth gradients of metal-ion concentrations in passive films on stainlesssteel using angle-resolved X-ray photoelectron spectroscopy (ARXPS) is described. The iterative method,which is based on analyses of the oxidised metal peaks, provides increased precision and hence allowsfaster ARXPS measurements to be carried out. The method was used to determine the concentrationdepth profiles for molybdenum, iron and chromium in passive films on 316L/EN 1.4432 stainless steelsamples oxidised in 0.5 M H2SO4 and acetic acid diluted with 0.02 M Na2B4O7 · 10H2O and 1 M H2O,respectively. The molybdenum concentration in the film is pin-pointed to the oxide/metal interface andthe films also contained an iron-ion-enriched surface layer and a chromium-ion-dominated middle layer.Although films of similar composition and thickness (i.e., about 2 nm) were formed in the two electrolytes,the corrosion currents were found to be three orders of magnitude larger in the acetic acid solution.The differences in the layer composition, found for the two electrolytes as well as different oxidationconditions, can be explained based on the oxidation potentials of the metals and the dissolution rates ofthe different metal ions.

  • 47. Jastrebova, J
    et al.
    Nyholm, L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Markides, K
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Bergqvist, Y
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    On-Line Deoxygenation for Reductive Electrochemical Detection of Artemisinin and Dihydroartemisinin in Liquid Chromatography1998In: The Analyst, ISSN 0003-2654, Vol. 123, p. 313-Article in journal (Refereed)
  • 48.
    Jonsson, Jonas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Smedfors, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Towards chip-based salinity measurements for small submersibles and biologgers2013In: International Journal of Oceanography, ISSN 1687-9406, E-ISSN 1687-9414, Vol. 2013, p. 529674-Article in journal (Refereed)
    Abstract [en]

    Water’s salinity plays an important role in the environment. It can be determined by measuring conductivity, temperature, anddepth (CTD). The corresponding sensor systems are commonly large and cumbersome. Here, a 7.5 × 3.5mm chip, containingmicrostructured CTD sensor elements, has been developed. On this, 1.5mm2 gold finger electrodes are used to measure theimpedance, and thereby the conductivity of water, in the MHz frequency range. Operation at these frequencies resulted in highersensitivities than those at sub-MHz frequencies. Up to 14 kΩ per parts per thousand salt concentration was obtained repeatedlyfor freshwater concentrations.This was three orders of magnitude higher than that obtained for concentrations in and above thebrackish range. A platinumelectrode is used to determine a set ambient temperature with an accuracy of 0.005∘C.Membranes withNichrome strain gauges responded to a pressure change of 1 bar with a change in resistance of up to 0.21Ω. A linear fit to data over7 bars gave a sensitivity of 0.1185Ω/bar with an R2 of 0.9964. This indicates that the described device can be used in size-limitedapplications, like miniaturized submersibles, or as a bio-logger on marine animals.

  • 49.
    Karis, Olof
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Experimental Physics. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Department of Materials Chemistry, Inorganic Chemistry.
    Valizadeh, Sima
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Experimental Physics. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Department of Materials Chemistry, Inorganic Chemistry. Elektronmikroskopi.
    Surpi, Alessandro
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Experimental Physics. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Department of Materials Chemistry, Inorganic Chemistry. Istituto di Fotonica e Nanotecnologie (C.N.R.).
    HUNTER DUNN, J
    MAX-lab, Lund, Sweden..
    SVEDLINDH, PETER
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Experimental Physics. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Department of Materials Chemistry, Inorganic Chemistry.
    Stanciu, V
    Warnicke, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Experimental Physics. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Department of Materials Chemistry, Inorganic Chemistry.
    Sandell, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Experimental Physics. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Department of Materials Chemistry, Inorganic Chemistry.
    Nyholm, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Experimental Physics. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Sanyal, Biplab
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Experimental Physics. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Department of Materials Chemistry, Inorganic Chemistry.
    Eriksson, Olle
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Experimental Physics. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Solid State Physics. Department of Materials Chemistry, Inorganic Chemistry.
    Electronic and geometric structure of (Zn,Co)O room temperature Ferromagnets2005In: 50th MMM Meeting Program, 2005Conference paper (Refereed)
  • 50. Keskinen, Jari
    et al.
    Tuurala, Saara
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Kiri, Kaisa
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Flyktman, Timo
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Smolander, Maria
    Asymmetric and symmetric supercapacitors based on polypyrrole and activated carbon electrodes2015In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 203, p. 192-199Article in journal (Refereed)
    Abstract [en]

    Abstract Supercapacitors were prepared using either two polypyrrole (PPy) composite electrodes or one PPy composite and one activated carbon electrode. The PPy composite electrodes were either freestanding paper-like sheets or PPy films printed on graphite ink coated aluminium/PET laminate substrates, using Cladophora algae derived cellulose as the substrate or binder, respectively. The specific capacitance of the PPy electrodes was found to be about 200 F g−1 depending on the manufacturing method, yielding supercapacitors with capacitances between 0.45 and 3.8 F and energy efficiencies of over 90%. For an asymmetric device with activated carbon positive electrode and PPy negative electrode a capacitance loss of 5% was seen after 14300 cycles.

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