Equilibrium Lithium-Ion Transport Between Nanocrystalline Lithium-Inserted Anatase TiO2 and the Electrolyte

Authors

  • Dr. Swapna Ganapathy,

    1. Department of Radiation, Radionucleides and Reactors, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (The Netherlands), Fax: (+31) 15-27-88303
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  • Dr. Ernst R. H. van Eck,

    1. Solid-State NMR, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (The Netherlands)
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  • Prof. Dr. Arno P. M. Kentgens,

    1. Solid-State NMR, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (The Netherlands)
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  • Prof. Dr. Fokko M. Mulder,

    1. Department of Radiation, Radionucleides and Reactors, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (The Netherlands), Fax: (+31) 15-27-88303
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  • Dr. Marnix Wagemaker

    Corresponding author
    1. Department of Radiation, Radionucleides and Reactors, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (The Netherlands), Fax: (+31) 15-27-88303
    • Department of Radiation, Radionucleides and Reactors, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (The Netherlands), Fax: (+31) 15-27-88303
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Abstract

The power density of lithium-ion batteries requires the fast transfer of ions between the electrode and electrolyte. The achievable power density is directly related to the spontaneous equilibrium exchange of charged lithium ions across the electrolyte/electrode interface. Direct and unique characterization of this charge-transfer process is very difficult if not impossible, and consequently little is known about the solid/liquid ion transfer in lithium-ion-battery materials. Herein we report the direct observation by solid-state NMR spectroscopy of continuous lithium-ion exchange between the promising nanosized anatase TiO2 electrode material and the electrolyte. Our results reveal that the energy barrier to charge transfer across the electrode/electrolyte interface is equal to or greater than the barrier to lithium-ion diffusion through the solid anatase matrix. The composition of the electrolyte and in turn the solid/electrolyte interface (SEI) has a significant effect on the electrolyte/electrode lithium-ion exchange; this suggests potential improvements in the power of batteries by optimizing the electrolyte composition.

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