Surface coating of LiMn2O4 cathodes with garnet electrolytes for improving cycling stability of solid lithium batteries†
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 Li6.375La3Zr1.375Nb0.625O12 (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.