The stability between perovskite La_2/3-xLi_3x□_1/3-2xTiO₃ (3x = 0.3) electrolyte and LiM_mO_n (M = Mn, Ni and Co) cathodes

Perovskite La_2/3-xLi_3x□_1/3-2xTiO₃ (LLT) exhibits high lithium-ion conductivity (∼10^-3 S cm^-1) is a potential material for using as solid-state electrolyte in all-solid-state lithium-ion microbatteries. Considering about the LLT and cathode films might undergo high-temperature heat treatment simultaneously, the stability and reaction in the interface of electrolyte and cathode become interesting points to be investigated. In this study, LLT powders were mixed with three kinds of cathodes and then annealed at 500-800 °C. The results indicated that the LLT electrolyte was extremely stable with spinel LiMn₂O₄ even after 800 °C heat treatment for 2 h. The commercial cathode material, HT-LiCoO₂, also shows good stability with LLT electrolyte after 700 °C annealing, but the structures of LLT and LiCoO₂ both showed slight damage after 800 °C heat treatment. Moreover, layered LiNiO₂ showed poor stability with LLT, and, it decomposed into NiO when annealing with LLT above 500 °C.