Lithium-Ion Transfer at the Interface between High Potential Negative Electrodes and Ionic Liquids

We prepared Li4Ti5O12 (LTO) thin films as a high potential negative electrode by the sol-gel method and investigated the kinetics of lithium ion transfer at the interface between LTO thin film electrodes and ionic liquids by AC impedance spectroscopy. Activation energies for interfacial lithium ion transfer were evaluated based on the temperature dependences of the interfacial conductivities. We found that the activation energies for lithium ion transfer at electrodes/ionic liquids were higher, when compared with the case of conventional organic electrolytes. These higher activation energies for ionic liquids might be rationalized by the strong interaction between lithium ions and anion components of the ionic liquids. (C) 2014 The Electrochemical Society. All rights reserved.