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  • 801.
    Younesi, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Bardé, Fanny
    Toyota Motor Europe, Zaventem, Belgium.
    Electrochemical performance and interfacial properties of Li-metal in lithium bis(fluorosulfonyl)imide based electrolytes2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 15925Article in journal (Refereed)
    Abstract [en]

    Successful usage of lithium metal as the negative electrode or anode in rechargeable batteries can be an important step to increase the energy density of lithium batteries. Performance of lithium metal in a relatively promising electrolyte solution composed of lithium bis( uorosulfonyl)imide (LiN(SO2F)2; LiFSI) salt dissolved in 1,2-dimethoxyethane (DME) is here studied. The in uence of the concentration of the electrolyte salt −1 M or 4 M LiFSI- is investigated by varying important electrochemical parameters such as applied current density and plating capacity. X-ray photoelectron spectroscopy analysis as a surface sensitive technique is here used to analyze that how the composition of the solid electrolyte interphase varies with the salt concentration and with the number of cycles.

  • 802.
    Younesi, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brant, William
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Mogensen, Ronnie
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Larsson, Paul
    ALTRIS AB.
    A Cheap and Sustainable Cathode Material for Sodium Ion Batteries2017Conference paper (Other academic)
  • 803.
    Younesi, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Christiansen, Ane Sælland
    Technical University of Denmark.
    Scipioni, Roberto
    Technical University of Denmark.
    Ngo, Duc-The
    Technical University of Denmark.
    Simonsen, Søren Bredmose
    Technical University of Denmark.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Hjelm, Johan
    Technical University of Denmark.
    Norby, Poul
    Technical University of Denmark.
    Analysis of the Interphase on Carbon Black Formed in High Voltage Batteries2015In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 162, no 7, p. A1289-A1296Article in journal (Refereed)
    Abstract [en]

    Carbon black (CB) additives commonly used to increase the electrical conductivity of electrodes in Li-ion batteries are generally believed to be electrochemically inert additives in cathodes. Decomposition of electrolyte in the surface region of CB in Li-ion cells at high voltages up to 4.9 V is here studied using electrochemical measurements as well as structural and surface characterizations. LiPF6 and LiClO4 dissolved in ethylene carbonate:diethylene carbonate (1:1) were used as the electrolyte to study irreversible charge capacity of CB cathodes when cycled between 4.9 V and 2.5 V. Synchrotron-based soft X-ray photoelectron spectroscopy (SOXPES) results revealed spontaneous partial decomposition of the electrolytes on the CB electrode, without applying external current or voltage. Depth profile analysis of the electrolyte/cathode interphase indicated that the concentration of decomposed species is highest at the outermost surface of the CB. It is concluded that carboxylate and carbonate bonds (originating from solvent decomposition) and LiF (when LiPF6 was used) take part in the formation of the decomposed species. Electrochemical impedance spectroscopy measurements and transmission electron microscopy results, however, did not show formation of a dense surface layer on CB particles.

  • 804.
    Younesi, Reza
    et al.
    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.
    Björefors, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Johansson, Patrik
    Department of Applied Physics, Chalmers University of Technology.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Li-O2 Battery Degradation by Lithium Peroxide (Li2O2): A Model Study2013In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 25, no 1, p. 77-84Article in journal (Refereed)
    Abstract [en]

    The chemical stability of the Li-O2 battery components (cathode and electrolyte) in contact with lithiumperoxide (Li2O2) was investigated using X-ray photoelectron spectroscopy (XPS). XPS is a versatile method to detect amorphous as well as crystalline decomposition products of both salts and solvents. Two strategies were employed. First, cathodes including carbon, α‑MnO2 catalyst, and Kynar binder (PVdF-HFP) were exposed to Li2O2 and LiClO4 in propylenecarbonate (PC) or (tetraethylene glycol dimethyl ether) TEGDME electrolytes. The results indicated that Li2O2 degrades TEGDME to carboxylate containing species and that the decomposition products in turn degraded the Kynar binder. The α‑MnO2 catalyst was unaffected. Second, Li2O2 model surfaces were kept in contact with different electrolytes to investigate the chemical stability, and also the resulting surface layer on Li2O2. Further, the XPS experiments revealed that the Li salts LiPF6, LiBF4, and LiClO4 decomposed to form LiF or LiCl together with P-O or B-O bond containing compounds when exposed to Li2O2. PC decomposed to carbonate and ether based species. The degradation of the electrolytes increased from short to long exposure time indicating that the surface layer on Li2O2 became thicker by increasing time. Overall, it was shown that a mixture of ethylene carbonate and diethyl carbonate (EC/DEC) is more robust in contact with Li2O2 compared to PC.

  • 805.
    Younesi, Reza
    et al.
    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.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Degradation Products on Li-Negative Electrode and the Carbon Cathode in Li-O2 Batteries2012Conference paper (Refereed)
  • 806.
    Younesi, Reza
    et al.
    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.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Surface Characterization of the Carbon Cathode and the Lithium Anode of Li-O2 Batteries using LiClO4 or LiBOB salts2013In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 5, no 4, p. 1333-1341Article in journal (Refereed)
    Abstract [en]

    The surface compositions of a MnO2 catalyst containing carbon cathode and a Li anode in a Li–O2 battery were investigated using synchrotron-based photoelectron spectroscopy (PES). Electrolytes comprising LiClO4 or LiBOB salts in PC or EC:DEC (1:1) solvents were used for this study. Decomposition products from LiClO4 or LiBOB were observed on the cathode surface when using PC. However, no degradation of LiClO4 was detected when using EC/DEC. We have demonstrated that both PC and EC/DEC solvents decompose during the cell cycling to form carbonate and ether containing compounds on the surface of the carbon cathode. However, EC/DEC decomposed to a lesser degree compared to PC. PES revealed that a surface layer with a thickness of at least 1–2 nm remained on the MnO2 catalyst at the end of the charged state. It was shown that the detachment of Kynar binder influences the surface composition of both the carbon cathode and the Li anode of Li–O2 cells. The PES results indicated that in the charged state the SEI on the Li anode is composed of PEO, carboxylates, carbonates, and LiClO4 salt.

  • 807.
    Younesi, Reza
    et al.
    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.
    Roberts, Matthew
    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.
    The SEI Layer Formed on Lithium Metal in the Presence of Oxygen: A Seldom Considered Component in the Development of the Li-O2 battery2013In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 225, p. 40-45Article in journal (Refereed)
    Abstract [en]

    The SEI layer formed on metallic Li which has been used as an anode in a Li-O2 battery is studied for the first time. We have used XPS to monitor the surface composition of the lithium electrode and have identified the various chemical species present. The XPS results indicated that the composition of the SEI layer is affected by the presence of oxygen and is unstable during cycling. We also observed decomposition products from the binder material used in the cathode on the surface of the lithium anode. This new SEI layer has an increased resistance affecting the lithium deposition which is essential for battery operation.

  • 808.
    Younesi, Reza
    et al.
    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.
    Treskow, Marcel
    Department of Applied Physics, Chalmers University of Technology.
    Scheers, Johan
    Department of Applied Physics, Chalmers University of Technology.
    Johansson, Patrik
    Department of Applied Physics, Chalmers University of Technology.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ether Based Electrolyte, LiB(CN)4 Salt and Binder Degradation in the Li-€“O2 Battery Studied by Hard X-ray Photoelectron Spectroscopy (HAXPES)2012In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 35, p. 18597-18604Article in journal (Refereed)
    Abstract [en]

    Li-O2 cells composed of a carbon cathode containing an α-MnO2 nanowire catalyst and a Kynar (PVDF-HFP) binder were cycled with different electrolytes containing 0.5 M LiB(CN)4 salt in polyethylene glycol dimethyl ether (PEGDME) or tetraethylene glycol dimethyl ether (Tetraglyme) solvents. All cells exhibited fast capacity fading. To explain this, the surface chemistry of the carbon electrodes were investigated by synchrotron based hard X-ray photoelectron spectroscopy (HAXPES) using two photon energies of 2300 and 6900 eV. It is shown that the LiB(CN)4 salt and Kynar binder were degraded during cycling, forming a layer composed of salt and binder residues on the cathode surface. The degradation mechanism of the salt differed in the two tested solvents and, consequently, different types of boron compounds were formed during cycling. Larger amounts of the degraded salt was observed using Tetraglyme as the solvent. With a nonfluorined Li-salt, the observed formation of LiF, which might be a reason for the observed blockage of pores in the cathode and for the observed capacity fading, must be due to Kynar binder decomposition. The amount of LiF formed in the PEGDME cell was larger than that formed in the Tetraglyme cell. The results indicate that not only the electrolyte solvent, but also electrolyte salt as well as the binder used for the porous cathode must be carefully considered when building a successful rechargeable Li-O2 battery.

  • 809.
    Younesi, Reza
    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.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Tan, Serdar
    Akdeniz University.
    Influence of annealing temperature on the electrochemical and surface properties of the 5-V spinel cathode material LiCr0.2Ni0.4Mn1.4O4 synthesized by a sol–gel technique2014In: Journal of Solid State Electrochemistry, ISSN 1432-8488, E-ISSN 1433-0768, Vol. 18, no 8, p. 2157-2166Article in journal (Refereed)
    Abstract [en]

    LiCr0.2Ni0.4Mn1.4O4 was synthesized by a sol-gel technique in which tartaric acid was used as oxide precursor. The synthesized powder was annealed at five different temperatures from 600 to 1,000 A degrees C and tested as a 5-V cathode material in Li-ion batteries. The study shows that annealing at higher temperatures resulted in improved electrochemical performance, increased particle size, and a differentiated surface composition. Spinel powders synthesized at 900 A degrees C had initial discharge capacities close to 130 mAh g(-1) at C and C/2 discharge rates. Powders synthesized at 1,000 A degrees C showed capacity retention values higher than 85 % at C/2, C, and 2C rates at 25 A degrees C after 50 cycles. Annealing at 600-800 A degrees C resulted in formation of spinel particles smaller than 200 nm, while almost micron-sized particles were obtained at 900-1,000 A degrees C. Chromium deficiency was detected at the surface of the active materials annealed at low temperatures. The XPS results indicate presence of Cr6+ impurity when the annealing temperature was not high enough. The study revealed that increased annealing temperature is beneficial for both improved electrochemical performance of LiCr0.2Ni0.4Mn1.4O4 and for avoiding formation of Cr6+ impurity on its surface.

  • 810.
    Younesi, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Singh, Neelam
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Urbonaite, Sigita
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    The Effect of Pore Size on the Performance of the Li-O2 Battery2010In: ECS Transactions, ISSN 1938-5862, E-ISSN 1938-6737, Vol. 25, no 35, p. 121-127Article in journal (Refereed)
    Abstract [en]

    Lithium-airbatteries are complex electrochemical systems. This study deals with thecomposite cathode, where oxygen is reduced and different lithium-oxygen speciesare formed as reaction products. The amount of stored reactionproduct and thus the battery capacity is known to dependon surface area and pore-volume in the cathode. Here therole of pore size is studied for three different carbonsand their corresponding composite cathode films. Gas adsorption studies showthat film-forming Kynar polymer is blocking micropores and mesopores below~300 Å. This influences battery performance of the high surfacearea carbon, containing micropores only, where the capacity is shownto be negligible. The two other carbons, with wider pore-sizedistributions, show a battery capacity in the order of 1300-1500mAh/g carbon. This shows that it is vital to consideralso the pore size in the cathode film for agood battery performance.

  • 811.
    Younesi, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Singh, Neelam
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Urbonaite, Sigita
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    The Primary Nonaqueous Lithium-Air Battery2009Conference paper (Other academic)
  • 812.
    Younesi, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Urbonaite, Sigita
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    The Role of Carbon in the Cathode of a Li-O2 Battery2010Conference paper (Refereed)
  • 813.
    Younesi, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Urbonaite, Sigita
    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.
    Hahlin, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    The Cathode Surface Composition of a Cycled Li–O2 Battery: A Photoelectron Spectroscopy Study2012In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 39, p. 20673-20680Article in journal (Refereed)
    Abstract [en]

    A layer of reaction products, dominantly built up of C and O in the form of ethers and lithium alkyl carbonates, is formed on the surface of the carbon cathode during discharge of a Li–O2 battery in an electrolyte of 1 M LiPF6 in PC. The results are based on a detailed surface analysis combining the use of in house X-ray photoelectron spectroscopy (XPS) and synchrotron based hard X-ray photoelectron spectroscopy (HAXPES). The Li–O2 batteries were investigated at uncycled state (stored), after the first discharge, after the first charge, and at the end of life (discharge state). The results showed little to no Li2O2 and/or Li2O among the discharge products. The surface layers on the cathode were dominantly removed during charging of the battery. At the end of battery life, no complete discharge product layer is formed. The cathodes showed a strong indication of binder decomposition during cycling of the Li–O2 cell. Overall, the results obtained in this investigation show that the whole cathode formulation as well as the electrolyte composition need a completely new approach for the realization of a recyclable Li–O2 battery.

  • 814.
    Younesi, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Veith, Gabriel M.
    Oak Ridge National Laboratory.
    Johansson, Patrik
    Chalmers University of Technology.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Vegge, Tejs
    Technical University of Denmark.
    Lithium salts for advanced lithium batteries: Li-metal, Li-O2, and Li-S2015In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 8, no 7, p. 1905-1922Article, review/survey (Refereed)
    Abstract [en]

    Presently lithium hexafluorophosphate (LiPF6) is the dominant Li-salt used in commercial rechargeable lithium-ion batteries (LIBs) based on a graphite anode and a 3-4 V cathode material. While LiPF6 is not the ideal Li-salt for every important electrolyte property, it has a uniquely suitable combination of properties (temperature range, passivation, conductivity, etc.) rendering it the overall best Li-salt for LIBs. However, this may not necessarily be true for other types of Li-based batteries. Indeed, next generation batteries, for example lithium-metal (Li-metal), lithium-oxygen (Li-O2), and lithium-sulfur (Li-S), require a re-evaluation of Li-salts due to the different electrochemical and chemical reactions and conditions within such cells. This review explores the critical role Li-salts play in ensuring in these batteries viability.

  • 815.
    Younesi, S Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Urbonaite, Sigita
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Björefors, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Influence of the Cathode Porosity on the Discharge Performance of the Lithium-Oxygen Battery2011In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 196, no 22, p. 9835-9838Article in journal (Refereed)
    Abstract [en]

    By varying the ratio between the amount of carbon and Kynar binder in the cathode of a lithium-oxygen battery, it could be shown that an increasing amount of binder resulted in a decrease in the discharge capacity, mainly as a result of the decrease in the cathode porosity. It was shown that the Kynar binder blocked the majority of the pores with a width below 300 angstrom as determined by studying the pore volume and pore size distribution by nitrogen adsorption. Three carbonate based electrolytes (PC, PC:DEC (1:1), and EC:DEC (2:1) with 1 M LiPF(6)) were tested with the various cathode film compositions. Generally, the PC:DEC and EC:DEC based electrolytes provided higher capacities than PC. The results indicated that the air electrode composition and its effect on the porosity of the cathode, as well as electrolyte properties, are important when optimizing the discharge capacity.

  • 816. Zadin, Vahur
    et al.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Electrochemical simulations of 3D-battery architectures2015In: SolidState Battery Handbook / [ed] Nancy J. Dudney, William C West, Jagjit Nanda, Singapore: World Scientific , 2015, 2, p. 731-777Chapter in book (Refereed)
  • 817. Zadin, Vahur
    et al.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Kasemaegi, Heiki
    Lellep, Jaan
    Aabloo, Alvo
    Designing the 3D-microbattery geometry using the level-set method2013In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 244, p. 417-428Article in journal (Refereed)
    Abstract [en]

    Strategies for automatic design of power-optimized 3D-microbattery geometries are here investigated by utilization of the level-set method with structure topology optimization. The methodology is extended from solid mechanics to electrochemical systems, where battery operation is simulated using the Nernst-Planck equation. The calculations are carried out for the 3D-"trench" geometry with LiCoO2 and LiC6 as electrodes, separated with a LiPF6 center dot PEO20 Polyethylene oxide polymer electrolyte. With the goal to achieve a maximum uniform electrochemical activity over the electrode surface area, an optimized electrode design is produced by coating the current collectors non-uniformly with active material. This is shown to be an effect of the 3D design of the cell. Evaluation of the resulting optimized cell by simulations of the discharge process demonstrates uniform electrode material utilization and almost uniform current density distribution over the entire electrode-electrolyte interface. Comparisons between optimized and non-optimized geometries showed that the geometry optimization increased the cell performance up to 2.25 times. This effect is mainly achieved by minimizing the internal energy losses caused by non-uniformities in the ionic transport in the battery.

  • 818. Zadin, Vahur
    et al.
    Danilov, Dmitry
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Notten, Peter H. L.
    Aabloo, Alvo
    Finite element simulations of 3D ionic transportation properties in Li-ion electrolytes2012In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 65, p. 165-173Article in journal (Refereed)
    Abstract [en]

    In current work, the ionic transport limitations in the Li-ion battery liquid electrolyte with separator are studied by a finite element method. This theoretical approach is based on the Nernst-Planck equation. It is shown that instead of solving coupled PDE system for concentration and potential, it is sufficient to calculate only the concentration profile in a three-dimensional (3D) structure to obtain a full description of the diffusion-migration ionic transport in the electrolyte in the steady-state. Subsequently, the overpotential and electric field can be calculated by using the provided equations. It was found that diffusion and migration overpotentials are equal in the steady-state. Consequently, two algorithms exploiting electrolyte simulations are proposed and successfully used to calculate the limiting current for the simulated battery system. In the present study a single perforated layer of the separator is inserted into the electrolyte and the simulations are carried out by increasing the complexity of the membrane holes. The ionic transportation dependence on the pore shape was found to be local and limited by the spatial area around the perforated separator.

  • 819. Zeng, Wen
    et al.
    Ma, Ming-Guo
    Zhu, Jie-Fang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Cao, Shao-Wen
    Development and Fabrication of Advanced Materials for Energy and Environment Applications2013In: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, p. 279309-Article in journal (Other academic)
  • 820. Zhang, Biaobiao
    et al.
    Chen, Hong
    Daniel, Quentin
    Philippe, Bertrand
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Yu, Fengshou
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Li, Yuanyuan
    Ambre, Ram B.
    Zhang, Peili
    Li, Fei
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Sun, Licheng
    Defective and “c-Disordered” Hortensia-like Layered MnOx as an Efficient Electrocatalyst for Water Oxidation at Neutral pH2017In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 7, no 9, p. 6311-6322Article in journal (Refereed)
    Abstract [en]

    The development of a highly active manganese-based water oxidation catalyst in the design of an ideal artificial photosynthetic device operating under neutral pH conditions remains a great challenge, due to the instability of pivotal Mn3+ intermediates. We report here defective and “c-disordered” layered manganese oxides (MnOx-300) formed on a fluorine-doped tin oxide electrode by constant anodic potential deposition and subsequent annealing, with a catalytic onset (0.25 mA/cm2) at an overpotential (η) of 280 mV and a benchmark catalytic current density of 1.0 mA/cm2 at an overpotential (η) of 330 mV under neutral pH (1 M potassium phosphate). Steady current density above 8.2 mA/cm2 was obtained during the electrolysis at 1.4 V versus the normal hydrogen electrode for 20 h. Insightful studies showed that the main contributing factors for the observed high activity of MnOx-300 are (i) a defective and randomly stacked layered structure, (ii) an increased degree of Jahn–Teller distorted Mn3+ in the MnO6 octahedral sheets, (iii) effective stabilization of Mn3+, (iv) a high surface area, and (v) improved electrical conductivity. These results demonstrate that manganese oxides as structural and functional models of an oxygen-evolving complex (OEC) in photosystem II are promising catalysts for water oxidation in addition to Ni/Co-based oxides/hydroxides.

  • 821.
    Zhang, Biaobiao
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Li, Yuanyuan
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Fan, Lizhou
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Daniel, Quentin
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Zhang, Peili
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Wang, Linqin
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Sun, Licheng
    KTH Royal Institute of Technology, Stockholm, Sweden; Dalian University of Technology, Dalian, China.
    Electrocatalytic Water Oxidation Promoted by 3 D Nanoarchitectured Turbostratic δ-MnOx on Carbon Nanotubes2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 22, p. 4472-4478Article in journal (Refereed)
    Abstract [en]

    The development of manganese-based water oxidation electrocatalysts is desirable for the production of solar fuels, as manganese is earth-abundant, inexpensive, non-toxic, and has been employed by the Photosystem II in nature for a billion years. Herein, we directly constructed a 3 D nanoarchitectured turbostratic δ-MnOx on carbon nanotube-modified nickel foam (MnOx/CNT/NF) by electrodeposition and a subsequent annealing process. The MnOx/CNT/NF electrode gives a benchmark catalytic current density (10 mA cm−2) at an overpotential (η) of 270 mV under alkaline conditions. A steady current density of 19 mA cm−2 is obtained during electrolysis at 1.53 V for 1.0 h. To the best of our knowledge, this work represents the most efficient manganese-oxide-based water oxidation electrode and demonstrates that manganese oxides, as a structural and functional model of oxygen-evolving complex (OEC) in Photosystem II, can also become comparable to those of most Ni- and Co-based catalysts.

  • 822.
    Zhang, Chao
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Communication: Computing the Helmholtz capacitance of charged insulator-electrolyte interfaces from the supercell polarization2018In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 149, no 3, article id 031103Article in journal (Refereed)
    Abstract [en]

    Supercell modeling of an electrical double layer (EDL) at electrified solid-electrolyte interfaces is a challenge. The net polarization of EDLs arising from the fixed chemical composition setup leads to uncompensated EDLs under periodic boundary condition and convolutes the calculation of the Helmholtz capacitance [C. Zhang and M. Sprik, Phys. Rev. B 94, 245309 (2016)]. Here we provide a new formula based on the supercell polarization at zero electric field [C. Zhang and M. Sprik, Phys. Rev. B 94, 245309 (2016)]. Here we provide a new formula based on the supercell polarization at zero electric field (E ) over bar= 0 (i.e., standard Ewald boundary condition) to calculate the Helmholtz capacitance of charged insulator-electrolyte interfaces and validate it using atomistic simulations. Results are shown to be independent of the supercell size. This formula gives a shortcut to compute the Helmholtz capacitance without locating the zero net charge state of EDL and applies directly to any standard molecular dynamics code where the electrostatic interactions are treated by the Ewald summation or its variants.

  • 823.
    Zhang, Chao
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Note: On the dielectric constant of nanoconfined water2018In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 148, no 15, article id 156101Article in journal (Refereed)
  • 824.
    Zhang, Chao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Huffer, Jurg
    Univ Zurich, Inst Chem, Winterthurerstr 190, CH-8057 Zurich, Switzerland.
    Sprik, Michiel
    Univ Cambridge, Dept Chem, Lensfield Rd, Cambridge CB2 1EW, England.
    Coupling of Surface Chemistry and Electric Double Layer at TiO2 Electrochemical Interfaces2019In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 10, no 14, p. 3871-3876Article in journal (Refereed)
    Abstract [en]

    Surfaces of metal oxides at working conditions are usually electrified because of the acidbase chemistry. The charged interface compensated with counterions forms the so-called electric double layer. The coupling of surface chemistry and the electric double layer is considered to be crucial but is poorly understood because of the lack of information at the atomistic scale. Here, we used the latest development in density functional theory-based finite-field molecular dynamics simulation to investigate the pH dependence of the Helmholtz capacitance at electrified rutile TiO2(110)-NaCl electrolyte interfaces. It is found that, because of competing forces from surface adsorption and from the electric double layer, water molecules have a stronger structural fluctuation at high pH, and this leads to a much larger capacitance. It is also seen that interfacial proton transfers at low pH increase significantly the capacitance value. These findings elucidate the microscopic origin of the same trend observed in titration experiments.

  • 825.
    Zhang, Chao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Sprik, Michiel
    Supercell Modeling of Charged Solid-Liquid Interfaces2017Conference paper (Other academic)
  • 826.
    Zhang, Hao
    et al.
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China.
    Shi, Liyi
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China;Shanghai Univ, Emerging Ind Inst, Jiaxing 314006, Zhejiang, Peoples R China.
    Zhao, Yin
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China.
    Wang, Zhuyi
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China.
    Chen, Haijun
    Nankai Univ, Sch Elect Informat & Opt Engn, Tianjin 300350, Peoples R China.
    Zhu, Jie-Fang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Yuan, Shuai
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China;Shanghai Univ, Emerging Ind Inst, Jiaxing 314006, Zhejiang, Peoples R China.
    A simple method to enhance the lifetime of Ni-rich cathode by using low-temperature dehydratable molecular sieve as water scavenger2019In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 435, article id 226773Article in journal (Refereed)
    Abstract [en]

    Ni-rich cathode materials have received much attention because of their high specific capacity, low cost and environmentally friendly characteristic. However, the nickel-rich cathode is extremely sensitive to moisture, which results in poor structure stability and electrochemical performance. Herein, we demonstrate an efficient and simple route to prolong the lifetime of nickel-rich cathode by introducing a low-temperature dehydratable molecular sieve as water scavenger. The residual water content in electrolyte measurement and nuclear magnetic resonance test manifest that molecular sieve can effectively fix the trace H2O and reduce the decomposition rate of electrolyte from 16.6% to 4.0%, respectively. Transmission electron microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy confirm that the molecular sieve inhibits the fragmentation of the electrode and the side reactions on the surface of the cathode. This approach improves structural integrity and stabilizes surface structure of the cathode, which increases the capacity retention without sacrificing rate performance. This effective strategy can be extended to other cathode materials which are sensitive to moisture to realize good cycling stability.<bold> </bold>

  • 827.
    Zhang, Jinbao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Pazoki, Meysam
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Simiyu, Justus
    Univ Nairobi, Dept Phys, POB 30197-00100, Nairobi, Kenya.
    Johansson, Malin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Cheung, Ocean
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Häggman, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johansson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Vlachopoulos, Nick
    SB ISIC LSPM, Ecole Polytech Fed Lausanne, Lab Photomol Sci, Chemin Alamb,Stn 6,CH G1 523, CH-1015 Lausanne, Switzerland.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. SB ISIC LSPM, Ecole Polytech Fed Lausanne, Lab Photomol Sci, Chemin Alamb,Stn 6,CH G1 523, CH-1015 Lausanne, Switzerland.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    The effect of mesoporous TiO2 pore size on the performance of solid-state dye sensitized solar cells based on photoelectrochemically polymerized Poly(3,4-ethylenedioxythiophene) hole conductor2016In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 210, p. 23-31Article in journal (Refereed)
    Abstract [en]

    Photoelectrochemical polymerization of poly(3,4-ethylenedioxythiphene) (PEDOT) has recently been introduced and widely investigated for fabrication of the hole transporting material (HTM) in highly efficient solid state dye sensitized solar cells (sDSCs). In this work, the effects of the surface area and pore size of TiO2 film were for the first time investigated in the sDSCs employing the in-situ polymerizated PEDOT HTM. Three different varieties of mesoporous TiO2 particles with controllable surface area and pore size were synthesized through the basic route in order to study the corresponding sDSC photovoltaic performances. It was found that the pore size plays an important role in the kinetics of the photoelectrochemical polymerization (PEP) process and the formation of the PEDOT capping layer. Larger pore sizes provided a more favourable pathway for the precursor diffusion through the mesoporous pores during the PEP process, which contributed towards a more efficient PEP. However, the interfacial contact area between the formed polymer and the dyes on the surface of TiO2 particle would be lower in the case of larger pore sizes, which consequently caused a less efficient dye regeneration process. Electronic diffusion on the other hand was improved for larger particle sizes. Employing an organic dye LEG4 and the self-made TiO2 with an optimal pore size of 25 nm and particle size of 24 nm, the sDSCs showed a promising power conversion efficiency (PCE) of 5.2%, higher than 4.5% for the commercial TiO2 Dyesol DSL-30. By measuring the dye regeneration yield and the kinetics through photoinduced absorption, it was observed that the homemade TiO2 based device had more efficient dye regeneration compared to the Dyesol based device, which could result from the better interfacial contact between the PEDOT and the dye. This work provides important information on the effect of meso-pore size on sDSCs and points to the necessity of further photoanode optimization toward the enhancement of the PCE of polymeric hole conductor-based DSCs.

  • 828.
    Zhang, Keliang
    et al.
    Qilu Univ Technol, Shandong Acad Sci, Coll Mat Sci & Engn, Jinan 250353, Shandong, Peoples R China.
    Zhang, Xudong
    Qilu Univ Technol, Shandong Acad Sci, Coll Mat Sci & Engn, Jinan 250353, Shandong, Peoples R China.
    He, Wen
    Qilu Univ Technol, Shandong Acad Sci, Coll Mat Sci & Engn, Jinan 250353, Shandong, Peoples R China.
    Xu, Wangning
    Qilu Univ Technol, Shandong Acad Sci, Coll Mat Sci & Engn, Jinan 250353, Shandong, Peoples R China.
    Xu, Guogang
    Shandong Univ Sci & Technol, Coll Mat Sci & Engn, Qingdao 266590, Shandong, Peoples R China.
    Yi, Xinli
    Qilu Univ Technol, Shandong Acad Sci, Coll Mat Sci & Engn, Jinan 250353, Shandong, Peoples R China.
    Yang, Xuena
    Qilu Univ Technol, Shandong Acad Sci, Coll Mat Sci & Engn, Jinan 250353, Shandong, Peoples R China.
    Zhu, Jie-Fang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Rational design and kinetics study of flexible sodium-ion full batteries based on binder-free composite film electrodes2019In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 16, p. 9890-9902Article in journal (Refereed)
    Abstract [en]

    A high-performance flexible sodium-ion full battery (FSIFB) is developed by using binder-free composite film (BFCF) electrodes without using conductive carbon and current collectors. Hard carbon fibers decorated with different electrochemical active materials are used as the supporting framework and 3D conductive network of FSIFBs for the first time. Different pre-sodiated anodes and the electrolyte additives are designed for well-matched FSIFBs. Using a porous Na3V2(PO4)(3) coated hard carbon fiber film with a mass loading of 2.34 mg cm(-2) as the cathode and a pre-sodiated graphene/SiC/hard carbon fiber film with a mass loading of 1.50 mg cm(-2) as the anode, an optimized FSIFB is designed. It delivers high output voltage (3.34 V), high energy density (234.1 W h kg(-1) at a high-current rate of 0.5 A g(-1)), ultralong cyclability (over 2905 cycles at 0.5 A g(-1) and 1000 cycles at 5 A g(-1)), and high coulombic efficiency (approaching 100%), which surpasses those of all FSIFBs reported so far. Furthermore, this FSIFB still maintains good electrochemical attributes even at serious bending states in water. The models of the solid electrolyte interphase behavior on the surface of electrodes in the FSIFB are studied by using EIS, and a reaction mechanism and an equivalent electrical circuit are proposed. We also provide the videos of the preparation process for a pouch-type FSIFB to demonstrate its simple operability and potential applications.

  • 829.
    Zhang, Xue-Ming
    et al.
    Beijing Forestry Univ, Coll Mat Sci & Technol, Beijing Key Lab Lignocellulos Chem, Beijing 100083, Peoples R China..
    Ma, Ming-Guo
    Beijing Forestry Univ, Coll Mat Sci & Technol, Beijing Key Lab Lignocellulos Chem, Beijing 100083, Peoples R China..
    Yang, Jun
    Univ British Columbia, Vancouver, BC, Canada..
    Xiang, Zhouyang
    Univ Wisconsin, Madison, WI USA..
    Zhu, Jie-Fang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Alias, Yatimah
    Univ Malaya, Kuala Lumpur, Malaysia..
    Recent Advances in Cellulose-Based Materials: Synthesis, Characterization, and Their Applications2016In: International Journal of Polymer Science, ISSN 1687-9422, E-ISSN 1687-9430, article id 8730573Article in journal (Other academic)
  • 830.
    Zhansheng, Lu
    et al.
    College of Physics and Information Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
    Kullgren, Jolla
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Yang, Zongxian
    College of Physics and Information Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
    Hermansson, Kersti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Sulfidation of ceria surfaces from sulfur and sulfur diffusion2012In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 15, p. 8417-8425Article in journal (Refereed)
    Abstract [en]

    Even very low levels of sulfur contaminants can degrade the catalytic performance of cerium oxide. Here, the interaction of atomic sulfur with the ceria (111) and (110) surfaces has been studied using first-principles methods. Two sulfoxy species are identified: oxido-sulfate(2-) species (SO2-) on both the CeO2 (111) and (110) surfaces and hyposulfite (SO22-) on the (110) surface. Sulfide (S2-) is formed when a surface or a subsurface oxygen atoms is replaced by sulfur. These sulfide species are most stable at the surface. Furthermore, sulfite (SO32-) structures are found when sulfur is made to replaces one Ce in the ceria (111) and (110) surfaces. The calculated sulfur diffusion barriers are larger than 1.4 eV for both surfaces and thus sulfur is essentially immobile, providing a possible explanation for the sulfidation phenomena of the ceria-based catalysis. Thus we find three different species from interaction of S with Ceria which are all, due to their strong binding, capable of poisoning the surface, reduced or unreduced. Our results suggest that under reducing conditions, sulfur is likely to be found in the (111) surface (replacing oxygen) but on the (110) surface (as SO22-).

  • 831. Zheng, Lirong
    et al.
    Chen, Chongqi
    Zheng, Yuanhui
    Zhan, Yingying
    Cao, Yanning
    Lin, Xingyi
    Zheng, Qi
    Wei, Kemei
    Zhu, Jiefang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Photocatalytic activity of ZnO/Sn1-xZnxO2-x nanocatalysts: A synergistic effect of doping and heterojunction2014In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 148, p. 44-50Article in journal (Refereed)
    Abstract [en]

    A novel configuration of porous ZnO/Sn1-xZnxO2-x, heterojunction nanocatalyst with high photocatalytic activity was successfully synthesized through a simple two-step solvothermal method. Porous Sn1-xZnxO2, was synthesized from Zn2+ and Sn4+ precursors with the Zn/Sn ratio of 2:1 in the absence of alkali, and then intermolecular dehydrolysis led to the formation of heterointerface between Sn1-xZnxO2, and ZnO. The results show that Zn2+ doping exhibits a significant influence on particle size of SnO2 leading to much higher specific surface area and larger band gap, which is in favor of the photocatalytic activity of SnO2 under UV light irradiation. In addition, the formation of ZnO/Sn1-xZnxO2 heterostructure improves the separation of photogenerated electron hole pairs due to the potential difference between Sn1-xZnxO2, and ZnO, which also benefits to photocatalysis. By taking account of them together, these results provide further insight into the synergistic effects of metal ion doping and semiconductor/semiconductor heterostructure on the activity of photocatalysts in environmental remediation applications. (C) 2013 Elsevier B.V. All rights reserved.

  • 832.
    Zhu, Jiefang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Photocatalysts for Hydrogen Production2015In: Advanced Materials For Clean Energy / [ed] Xu, Q; Kobayashi, T, CRC PRESS-TAYLOR & FRANCIS GROUP , 2015, p. 391-419Chapter in book (Refereed)
  • 833.
    Zukowski, Samual R.
    et al.
    Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.
    Mitev, Pavlin D.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Hermansson, Kersti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ben-Amotz, Dor
    Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.
    CO2 Hydration Shell Structure and Transformation2017In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 8, no 13, p. 2971-2975Article in journal (Refereed)
    Abstract [en]

    The hydration-shell of CO2 is characterized using Raman multivariate curve resolution (Raman-MCR) spectroscopy combined with ab initio molecular dynamics (AIMD) vibrational density of states simulations, to validate our assignment of the experimentally observed high-frequency OH band to a weak hydrogen bond between water and CO2. Our results reveal that while the hydration-shell of CO2 is highly tetrahedral, it is also occasionally disrupted by the presence of entropically stabilized defects associated with the CO2-water hydrogen bond. Moreover, we find that the hydration-shell of CO2 undergoes a temperature-dependent structural transformation to a highly disordered (less tetrahedral) structure, reminiscent of the transformation that takes place at higher temperatures around much larger oily molecules. The biological significance of the CO2 hydration shell structural transformation is suggested by the fact that it takes place near physiological temperatures.

  • 834. Zöttl, S.
    et al.
    Schöbel, H.
    Bartl, P.
    Leidlmair, C.
    Daxner, M.
    Denifl, S.
    Märk, T. D.
    Scheier, P.
    Spångberg, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Mauracher, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Bohme, D. K.
    Energy harvesting in doped helium nano-droplets2012In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 388, no 13, p. 132003-Article in journal (Refereed)
    Abstract [en]

    We report the observation of sequential Penning ionization of dopants by metastable helium atoms in helium nano-droplets resulting in doubly charged ions. Strong charge induced dipole-interaction between the excited helium atom and the target ion provides a high probability for the transfer of the internal energy of the excited helium atom to the dopant ion. This process may also lead subsequently to a Coulomb explosion of molecular or cluster dopants.

  • 835.
    Åkerlund, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Emanuelsson, Rikard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hernández, Guiomar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ruipérez, F.
    Casado, N.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mecerreyes, D.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    The proton trap battery: Enabling reversible hydroquinone energy storage in organic electrolytes2019In: Organic Battery Days 2019., 2019Conference paper (Refereed)
  • 836.
    Åkerlund, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Emanuelsson, Rikard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hernández, Guiomar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ruipérez, Fernando
    Casado, Nerea
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mecerreyes, David
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    In situ Investigations of a Proton Trap Material: A PEDOT-Based Copolymer with Hydroquinone and Pyridine Side Groups Having Robust Cyclability in Organic Electrolytes and Ionic Liquids2019In: ACS Applied Energy Materials, ISSN 2574-0962, Vol. 2, no 6, p. 4486-4495Article in journal (Refereed)
    Abstract [en]

    A conducting redox polymer based on PEDOT with hydroquinone and pyridine pendant groups is reported and characterized as a proton trap material. The proton trap functionality, where protons are transferred from the hydroquinone to the pyridine sites, allows for utilization of the inherently high redox potential of the hydroquinone pendant group (3.3 V versus Li0/+) and sustains this reaction by trapping the protons within the polymer, resulting in proton cycling in an aprotic electrolyte. By disconnecting the cycling ion of the anode from the cathode, the choice of anode and electrolyte can be extensively varied and the proton trap copolymer can be used as cathode material for all-organic or metal-organic batteries. In this study, a stable and nonvolatile ionic liquid was introduced as electrolyte media, leading to enhanced cycling stability of the proton trap compared to cycling in acetonitrile, which is attributed to the decreased basicity of the solvent. Various in situ methods allowed for in-depth characterization of the polymer’s properties based on its electronic transitions (UV–vis), temperature-dependent conductivity (bipotentiostatic CV-measurements), and mass change (EQCM) during the redox cycle. Furthermore, FTIR combined with quantum chemical calculations indicate that hydrogen bonding interactions are present for all the hydroquinone and quinone states, explaining the reversible behavior of the copolymer in aprotic electrolytes, both in three-electrode setup and in battery devices. These results demonstrate the proton trap concept as an interesting strategy for high potential organic energy storage materials.

  • 837.
    Åkerlund, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Emanuelsson, Rikard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Renault, Stevén
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Strømme, Maria
    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.
    The Proton Trap Technology: Toward High Potential Quinone-Based Organic Energy Storage2017In: Advanced Energy Materials, ISSN 1614-6840, Vol. 7, no 20, article id 1700259Article in journal (Refereed)
    Abstract [en]

    An organic cathode material based on a copolymer of poly(3,4-ethylenedioxythiophene) containing pyridine and hydroquinone functionalities is described as a proton trap technology. Utilizing the quinone to hydroquinone redox conversion, this technology leads to electrode materials compatible with lithium and sodium cycling chemistries. These materials have high inherent potentials that in combination with lithium give a reversible output voltage of above 3.5 V (vs Li0/+) without relying on lithiation of the material, something that is not showed for quinones previously. Key to success stems from coupling an intrapolymeric proton transfer, realized by an incorporated pyridine proton donor/acceptor functionality, with the hydroquinone redox reactions. Trapping of protons in the cathode material effectively decouples the quinone redox chemistry from the cycling chemistry of the anode, which makes the material insensitive to the nature of the electrolyte cation and hence compatible with several anode materials. Furthermore, the conducting polymer backbone allows assembly without any additives for electronic conductivity. The concept is demonstrated by electrochemical characterization in several electrolytes and finally by employing the proton trap material as the cathode in lithium and sodium batteries. These findings represent a new concept for enabling high potential organic materials for the next generation of energy storage systems.

  • 838.
    Åvall, Gustav
    et al.
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden.
    Mindemark, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry. 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 Chemistry - Ångström, Structural Chemistry.
    Johansson, Patrik
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden.
    Sodium-Ion Battery Electrolytes: Modeling and Simulations2018In: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 8, no 17, article id 1703036Article, review/survey (Refereed)
    Abstract [en]

    The authors review the efforts made from a modeling and simulation perspective in order to assist both the fundamental understanding as well as the development of higher performance sodium-ion battery (SIB) electrolytes. Depending on the type of the electrolyte studied, liquid, ionic liquid, polymer, glass, solid-state, etc., the simulation methods applied and the research questions in focus differ, but all contribute to more rational progress. Furthermore, the authors create cases of meta-analysis using literature data. A historical perspective is applied and the focus clearly is on more recent work and novel electrolyte materials. Finally, the authors outline a few prospective areas for where SIB electrolyte simulations can/should be extended for maximum impact in the field.

  • 839.
    Österlund, Viking
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    High Energy Density Lithium-Sulfur Batteries obtained using Functional Binders2015Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
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