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Rehnlund, D., Pettersson, J., Edström, K. & Nyholm, L. (2018). Lithium trapping in microbatteries based on lithium- and Cu2O-coated copper nanorods. ChemistrySelect, 3(8), 2311-2314
Open this publication in new window or tab >>Lithium trapping in microbatteries based on lithium- and Cu2O-coated copper nanorods
2018 (English)In: ChemistrySelect, E-ISSN 2365-6549, Vol. 3, no 8, p. 2311-2314Article in journal (Refereed) Published
Abstract [en]

Microbatteries based on three-dimensional (3D) electrodes composed of thin films of Li and Cu2O coated on Cu nanorod current collectors by electrodeposition and spontaneous oxidation, respectively, are described and characterised electrochemically. High-resolution scanning electron microscopy (HR-SEM) data indicate that the Li electrodeposition resulted in a homogenous coverage of the Cu nanorods and elemental analyses were also used to determine the amount of lithium in the Li-coated electrodes. The results show that 3D Cu2O/Cu electrodes can be cycled versus 3D Li/Cu electrodes but that the capacity decreased during the cycling due to Li trapping in the Cu current collector of the 3D Li/Cu electrode. These findings highlight the problem of using copper current collectors together with metallic lithium as the formation of a solid solution yields considerable losses of electroactive lithium and hence capacity.

Keyword
lithium trapping, microbatteries, nanorods, Cu2O, copper
National Category
Inorganic Chemistry
Research subject
Chemistry with specialization in Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-343590 (URN)10.1002/slct.201800281 (DOI)000426495600015 ()
Funder
Swedish Research Council, 2012-4681, 2015-04421StandUpSwedish Energy Agency
Available from: 2018-02-28 Created: 2018-02-28 Last updated: 2018-05-31Bibliographically approved
Pan, R., Xu, X., Sun, R., Wang, Z., Lindh, J., Edström, K., . . . Nyholm, L. (2018). Nanocellulose Modified Polyethylene Separators for Lithium Metal Batteries. Small, 1-9, Article ID 1704371.
Open this publication in new window or tab >>Nanocellulose Modified Polyethylene Separators for Lithium Metal Batteries
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2018 (English)In: Small, p. 1-9, article id 1704371Article in journal (Refereed) Published
Abstract [en]

Abstract Poor cycling stability and safety concerns regarding lithium (Li) metal anodes are two major issues preventing the commercialization of high‐energy density Li metal‐based batteries. Herein, a novel tri‐layer separator design that significantly enhances the cycling stability and safety of Li metal‐based batteries is presented. A thin, thermally stable, flexible, and hydrophilic cellulose nanofiber layer, produced using a straightforward paper‐making process, is directly laminated on each side of a plasma‐treated polyethylene (PE) separator. The 2.5 µm thick, mesoporous (≈20 nm average pore size) cellulose nanofiber layer stabilizes the Li metal anodes by generating a uniform Li+ flux toward the electrode through its homogenous nanochannels, leading to improved cycling stability. As the tri‐layer separator maintains its dimensional stability even at 200 °C when the internal PE layer is melted and blocks the ion transport through the separator, the separator also provides an effective thermal shutdown function. The present nanocellulose‐based tri‐layer separator design thus significantly facilitates the realization of high‐energy density Li metal‐based batteries.

Keyword
cellulose, current distribution, lithium dendrites, lithium metal batteries, separators
National Category
Materials Chemistry Engineering and Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-349143 (URN)10.1002/smll.201704371 (DOI)
Available from: 2018-04-22 Created: 2018-04-22 Last updated: 2018-05-02Bibliographically approved
Wei, W., Valvo, M., Edström, K. & Nyholm, L. (2018). Size-dependent Electrochemical Performance of Monolithic Anatase TiO2 Nanotube Anodes for Sodium-ion Batteries. ChemElectroChem, 5(4), 674-684
Open this publication in new window or tab >>Size-dependent Electrochemical Performance of Monolithic Anatase TiO2 Nanotube Anodes for Sodium-ion Batteries
2018 (English)In: ChemElectroChem, Vol. 5, no 4, p. 674-684Article in journal (Refereed) Published
Abstract [en]

Well-defined, monolithic TiO2 nanotube thin films havebeen used as model anode electrodes to study Na-ion storage in anatase TiO2. It is shown that anatase TiO2 nanotubes with wall thicknesses up to 50 nm can be transformed into amorphous sodium titanate (e.g. Na0.2TiO2) nanotubes via an electrochemical activation process at about 0.2 V vs. Na+/Na. Due to the Na+ insertion and extraction reactions at about 0.55 and 0.75 V vs. Na+/Na, respectively, the activated TiO2 nanotubes exhibit reversible capacities of 170 mAh g-1. For the first time, it is shown that the nanotube length and wall thickness play critical roles in determining the electrochemical performances of this type of electrodes in Na-ion cells. An excellent rate performance, yielding capacities of about 33mAh g-1 at 20C and 161 mAh g-1 at C/5 rates, as well as a capacity retention of more than 97% after more than 350 cycles, could be achieved with nanotubes with a wall thickness of up to 20 nm. Thecycling rate for the nanotubes with a tube length of 4.5 μm should,however, be limited to 1C to guarantee a cycle life of about 200 cycles.

Keyword
TiO2, nanotubes, sodium, batteries, electrodes, free-standing, wall thickness, length
National Category
Inorganic Chemistry
Research subject
Chemistry with specialization in Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-337289 (URN)10.1002/celc.201701267 (DOI)000425380200015 ()
Funder
Swedish Research Council Formas, 245- 2014-668StandUp
Available from: 2017-12-21 Created: 2017-12-21 Last updated: 2018-05-07Bibliographically approved
Sun, B., Asfaw, H. D., Rehnlund, D., Mindemark, J., Nyholm, L., Edström, K. & Brandell, D. (2018). Towards Solid-State 3D-Microbatteries using Functionalized Polycarbonate-based Polymer Electrolytes. ACS Applied Materials and Interfaces, 10(3), 2407-2413
Open this publication in new window or tab >>Towards Solid-State 3D-Microbatteries using Functionalized Polycarbonate-based Polymer Electrolytes
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2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 3, p. 2407-2413Article in journal (Refereed) Published
Abstract [en]

3D-microbatteries (3D-MBs) impose new demands for theselection, fabrication and compatibility of the different battery components, notleast the electrolytes. Herein, solid polymer electrolytes (SPEs) based on poly(trimethylene carbonate) (PTMC) have been implemented in 3D-MB systems. 3D electrodes of two different architectures, LiFePO4-coated carbon foams and Cu2O-coated Cu nanopillars, have been coated with SPEs and used in Li-cells. Functionalized PTMC with hydroxyl end groups was found to enable uniform and well-covering coatings on LiFePO4-coated carbon foams, although the cell cycling performance was limited by the large SPE resistance. By employing a SPE prepared from a copolymer of TMC and caprolactone (CL), with higher ionic conductivity, Li-cells composed of Cu2O-coated Cu nanopillars were constructed and tested both at room temperature and 60 °C. The footprint areal capacity of the cells was ca. 0.02 mAh cm-2 for an area gain factor (AF) of 2.5, and 0.2 mAh cm-2 for a relatively dense nanopillar-array (AF=25) at a current density of 0.008 mA cm-2at ambient temperature (22±1 °C). These results provide new routes towards the realization of all-solid-state 3D-MBs.

Keyword
Li-battery, 3D-microbattery, polymer electrolyte, nanopillars, carbon foam, Cu2O, Cu, nanorods
National Category
Inorganic Chemistry Materials Chemistry
Research subject
Chemistry with specialization in Organic Chemistry; Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-336964 (URN)10.1021/acsmi.7b13788 (DOI)000423496500027 ()29199816 (PubMedID)
Funder
StandUp
Available from: 2017-12-19 Created: 2017-12-19 Last updated: 2018-03-16Bibliographically approved
Lindgren, F., Rehnlund, D., Källquist, I., Nyholm, L., Edström, K., Hahlin, M. & Maibach, J. (2017). Breaking Down a Complex System: Interpreting PES Peak Positions for Cycled Li-ion Battery Electrodes. The Journal of Physical Chemistry C, 121, 27303-27312
Open this publication in new window or tab >>Breaking Down a Complex System: Interpreting PES Peak Positions for Cycled Li-ion Battery Electrodes
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2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, p. 27303-27312Article in journal (Refereed) Published
Abstract [en]

Photoelectron spectroscopy (PES) is an important technique for tracing and understanding the side reactions responsible for decreasing performance of Li-ion batteries. Interpretation of different spectral components is dependent on correct binding energy referencing and for battery electrodes this is highly complex. In this work, we investigate the effect on binding energy reference points in PES in correlation to solid electrolyte interphase (SEI) formation, changing electrode potentials and state of charge variations in Li-ion battery electrodes. The results show that components in the SEI have a significantly different binding energy reference point relative to the bulk electrode material (i.e. up to 2 eV). It is also shown that electrode components with electronically insulating/semi-conducting nature are shifted as a function of electrode potential relative to highly conducting materials. Further, spectral changes due to lithiation are highly depending on the nature of the active material and its lithiation mechanism. Finally, a strategy for planning and evaluating PES experiments on battery electrodes is proposed where some materials require careful choice of one or more internal reference points while others may be treated essentially without internal calibration.

National Category
Physical Sciences Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-336952 (URN)10.1021/acs.jpcc.7b08923 (DOI)000418393900008 ()
Funder
Swedish Energy Agency, 40495-1EU, FP7, Seventh Framework Programme, Eurolion & HiCSwedish Research Council, 2016-03545VINNOVA, High Voltage ValleyStandUp
Available from: 2017-12-19 Created: 2017-12-19 Last updated: 2018-02-16Bibliographically approved
Wang, Z., Tammela, P., Strömme, M. & Nyholm, L. (2017). Cellulose-based Supercapacitors: Material and Performance Considerations. Advanced Energy Materials, 7(18), Article ID 1700130.
Open this publication in new window or tab >>Cellulose-based Supercapacitors: Material and Performance Considerations
2017 (English)In: Advanced Energy Materials, ISSN 1614-6832, Vol. 7, no 18, article id 1700130Article in journal (Refereed) Published
Abstract [en]

One of the biggest challenges we will face over the next few decades is finding a way to power the future while maintaining strong socioeconomic growth and a clean environment. A transition from the use of fossil fuels to renewable energy sources is expected. Cellulose, the most abundant natural biopolymer on earth, is a unique, sustainable, functional material with exciting properties: it is low-cost and has hierarchical fibrous structures, a high surface area, thermal stability, hydrophilicity, biocompatibility, and mechanical flexibility, which makes it ideal for use in sustainable, flexible energy storage devices. This review focuses on energy storage applications involving different forms of cellulose (i.e., cellulose microfibers, nanocellulose fibers, and cellulose nanocrystals) in supercapacitors, with particular emphasis on new trends and performance considerations relevant to these fields. Recent advances and approaches to obtaining high capacity devices are evaluated and the limitations of cellulose-based systems are discussed. For the first time, a combination of device-specific factors such as electrode structures, mass loadings, areal capacities, and volumetric properties are taken into account, so as to evaluate and compare the energy storage performance and to better assess the merits of cellulose-based materials with respect to real applications.

Place, publisher, year, edition, pages
WILEY: Wiley-VCH Verlagsgesellschaft, 2017
Keyword
cellulose, supercapacitor
National Category
Materials Chemistry Polymer Chemistry Engineering and Technology
Research subject
Chemistry; Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-333373 (URN)10.1002/aenm.201700130 (DOI)000411182500029 ()
Funder
Swedish Foundation for Strategic Research , RMA110012Stiftelsen Olle Engkvist ByggmästareSwedish Energy AgencyCarl Tryggers foundation
Available from: 2017-11-12 Created: 2017-11-12 Last updated: 2017-12-20Bibliographically approved
Böhme, S., Kerner, M., Scheers, J., Johansson, P., Edström, K. & Nyholm, L. (2017). Elevated Temperature Lithium-Ion Batteries Containing SnO2 Electrodes and LiTFSI-Pip14TFSI Ionic Liquid Electrolyte. Journal of the Electrochemical Society, 164(4), A701-A708
Open this publication in new window or tab >>Elevated Temperature Lithium-Ion Batteries Containing SnO2 Electrodes and LiTFSI-Pip14TFSI Ionic Liquid Electrolyte
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2017 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 4, p. A701-A708Article in journal (Refereed) Published
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.

National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-316877 (URN)10.1149/2.0861704jes (DOI)000400958600021 ()
Available from: 2017-03-07 Created: 2017-03-07 Last updated: 2017-06-14Bibliographically approved
Rehnlund, D., Lindgren, F., Bohme, S., Nordh, T., Zou, Y., Pettersson, J., . . . Nyholm, L. (2017). Lithium trapping in alloy forming electrodes and current collectors for lithium based batteries. Energy & Environmental Science, 10(6), 1350-1357
Open this publication in new window or tab >>Lithium trapping in alloy forming electrodes and current collectors for lithium based batteries
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2017 (English)In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 10, no 6, p. 1350-1357Article in journal (Refereed) Published
Abstract [en]

Significant capacity losses are generally seen for batteries containing high-capacity lithium alloy forming anode materials such as silicon, tin and aluminium. These losses are generally ascribed to a combination of volume expansion effects and irreversible electrolyte reduction reactions. Here, it is shown, based on e.g. elemental analyses of cycled electrodes, that the capacity losses for tin nanorod and silicon composite electrodes in fact involve diffusion controlled trapping of lithium in the electrodes. While an analogous effect is also demonstrated for copper, nickel and titanium current collectors, boron-doped diamond is shown to function as an effective lithium diffusion barrier. The present findings indicate that the durability of lithium based batteries can be improved significantly via proper electrode design or regeneration of the used electrodes.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2017
Keyword
LI-ION BATTERIES; ENERGY-STORAGE DEVICES; NEGATIVE ELECTRODES; ELECTROCHEMICAL LITHIATION; PHOTOELECTRON-SPECTROSCOPY; SILICON ELECTRODES; METAL ANODES; ELECTROLYTES; INSERTION; SURFACE
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-328278 (URN)10.1039/c7ee00244k (DOI)000403320300006 ()
Funder
Swedish Research Council, VR 2012-4681
Available from: 2017-12-20 Created: 2017-12-20 Last updated: 2017-12-28Bibliographically approved
Böhme, S., Edström, K. & Nyholm, L. (2017). Overlapping and rate controlling electrochemical reactions for tin(IV) oxide electrodes in lithiu-ion batteries. Journal of Electroanalytical Chemistry, 797, 47-60
Open this publication in new window or tab >>Overlapping and rate controlling electrochemical reactions for tin(IV) oxide electrodes in lithiu-ion batteries
2017 (English)In: Journal of Electroanalytical Chemistry, ISSN 0022-0728, E-ISSN 1873-2569, Vol. 797, p. 47-60Article in journal (Refereed) Published
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.

Keyword
Li-ion batteries, SnO2, electrodes, overlapping reactions
National Category
Inorganic Chemistry
Research subject
Chemistry with specialization in Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-336947 (URN)000404696900008 ()
Funder
Swedish Foundation for Strategic Research , EM11-0028StandUp
Available from: 2017-12-19 Created: 2017-12-19 Last updated: 2018-02-22Bibliographically approved
Asfaw, H. D., Tai, C.-W., Nyholm, L. & Edström, K. (2017). Over-Stoichiometric NbO2 Nanoparticles for a High Energy and Power Density Lithium Microbattery. CHEMNANOMAT, 3(9), 646-655
Open this publication in new window or tab >>Over-Stoichiometric NbO2 Nanoparticles for a High Energy and Power Density Lithium Microbattery
2017 (English)In: CHEMNANOMAT, ISSN 2199-692X, Vol. 3, no 9, p. 646-655Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2017
Keyword
3D microbattery, carbon foam, niobium oxide, over-stoichiometric, power
National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-335634 (URN)10.1002/cnma.201700141 (DOI)000409874100007 ()
Funder
StandUp
Available from: 2017-12-13 Created: 2017-12-13 Last updated: 2017-12-30
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9292-016X

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