A facile strategy to enhance the stability of Li-rich cathode: Electrochemical performance improvement and mechanism exploration

Lithium-rich layered materials are promising candidates for next generation Li-ion batteries (LIBs) due to high energy densities, which still, however, suffer low initial Coulombic efficiency (i.e. irreversible initial capacity loss), poor rate capability and capacity retention during cycling. In this work, Li+ conductive Li2SnO3 (LSO) is selected to modify the surface of Li1.2Mn0.56Ni0.17Co0.07O2 (LMNCO) without influencing its bulk structure. Electrochemical characterizations indicate that the obtained LSO@LMNCO electrode shows greatly improved cycling stability and rate capability compared with those of the pristine LMNCO. Intensive aging experiment reveals that the LSO modification layer plays a critical role in performance enhancement, which not only stabilizes the bulk structure of LMNCO in long-term storage/cycling via suppression of metal oxide dissolution, but also benefits the surface kinetics by growth inhibition of solid electrolyte interface (SEI) layer on the particle surface.