Stabilization of high-voltage layered oxide cathode by multi-electron rare earth oxide.

An ultrathin and uniform Sm 2 O 3 rare earth oxide functional coating is formed to enhance the lithium storage performance of high-voltage medium-nickel low-cobalt LiNi 0.6 Co 0.05 Mn 0.35 O 2 cathode. The multi-electron rare earth oxide functional coating improves electrode–electrolyte interfacial stability and bulk structural stability by acting as a physical passivation layer and charge compensation payer. [Display omitted] • An ultrathin and uniform Sm 2 O 3 rare earth oxide functional coating is obtained. • Sm 2 O 3 coating acts as a physical passivation layer and charge compensation payer. • Multi-electron Sm 2 O 3 coating enhances the interfacial lattice oxygen stability. • The interfacial, thermal, and bulk structural stability are improved. • An excellent high-voltage medium-nickel low-cobalt LiNi 0.6 Co 0.05 Mn 0.35 O 2 cathode. High-voltage medium-nickel low-cobalt lithium layered oxide materials have been recognized as a kind of promising cathodes to further promote the energy density of lithium-ion batteries (LIBs) due to their relatively high capacity, low cost, and improved safety. However, the high voltage induced bulk structure degradation and interfacial environment deterioration limit the performance liberation of this kind of cathodes. Here, an ultrathin and uniform Sm 2 O 3 rare earth oxide functional coating has been introduced to enhance the lithium storage performance of LiNi 0.6 Co 0.05 Mn 0.35 O 2 (NCM) cathode. On the one hand, this multi-electron Sm 2 O 3 function coating could increase the activation energy of surface lattice oxygen loss, improving the electrode–electrolyte interface stability; on the other hand, it delays the phase transition temperature and weakens the harmful H3 phase transition of NCM, improving its thermal stability as well as minimizing the mechanical degradation. These beneficial effects endowed by the Sm 2 O 3 coating imply that it could behave as both a physical passivation layer and a charge compensation payer. As a result, the 2%-Sm 2 O 3 @NCM delivers a higher capacity retention rate (97.3% vs 75.0% after 150 cycles) and a superior rate capacity (117 mAh g−1 vs 52 mAh g−1 at 5C) than the pristine NCM, making high-voltage lithium layered oxide one step closer to being a viable cathode. [ABSTRACT FROM AUTHOR]