Surface coating of LiMn2O4 cathodes with garnet electrolytes for improving cycling stability of solid lithium batteries

Abstract

Spinel lithium manganese oxide (LiMn₂O₄) is an attractive cathode material, and has advantages including low cost, environmental friendliness, and easy synthesis as well as shortcomings including inferior cycling stability at elevated temperatures above 55 °C. In this work, LiMn₂O₄ cathodes are coated with Li_6.375La₃Zr_1.375Nb_0.625O₁₂ (LLZNO) electrolytes. Such cathodes in solid batteries consisting of garnet ceramic electrolytes and Li anodes exhibit a discharge capacity retention of 81.3% after 100 cycles at 0.2C and 55 °C. This superior performance is attributed to the unique interface between LiMn₂O₄ and LLZNO, which is not only ionically conductive but also helpful to suppress Mn reactivity.