Charge Transfer across the Interface between LiNi0.5Mn1.5O4 High-Voltage Cathode Films and Solid Electrolyte Films

We have carried out a basic study on the charge transfer across the interface between LiNi0.5Mn1.5O4 (LNMO) thin-film cathodes and different solid electrolyte coatings, namely LiNbO3, ZrO2 and Li4Ti5O12. In contact to LNMO, the spinel material Li4Ti5O12 should act as a solid electrolyte, since it exhibits a very low electronic conductivity in the fully oxidized state. The thin films were prepared by means of sol-gel chemistry and spin-coating. The electrochemical and interfacial properties were studied by combining electrochemical impedance spectroscopy (EIS), time-of-flight secondary-ion mass spectrometry (ToF-SIMS) and cross-sectional SEM imaging. The results show that the LNMO/LiNbO3 interface combines a low charge transfer resistance with a high stability. (C) 2015 The Electrochemical Society. All rights reserved.