SURFACE MODIFICATIONS OF LI-MN-NI-O SPINEL THIN FILM CATHODES STUDIED BY X-RAY PHOTOELECTRON SPECTROSCOPY

摘要

Electrolyte decomposition, Mn dissolution and electrode passivation are critical issues preventing the use of high voltage of LiMn_(1.5)M_(0.5)O4 spinel cathodes in Li-ion batteries (1). One way to mitigate these issues involves coating LMNO with various insulating or conductive materials (1,2). This approach proved to be beneficial for improving the electrode cycle life. This improvement has often been attributed to the prevention of HF-induced Mn dissolution (2). It is also assumed that the coating material helps to keep the electrode surface sites active by separating physically the cathode surface from the electrolyte and its decomposition products.