Protective and ion conductive: Ni-rich cathode with enhanced electrochemical performance via dual-modification

Abstract

The advantages of affordable price and large capacity have made LiNixCoyMn1−x−yO2 (NCM) become a prominent topic in contemporary energy research. However, problems such as severe cation mixing and surface side reactions have critically hindered its commercial utilization. Herein, we propose a strategy of bulk-to-surface, namely Mo doping combined with LiBO2 coating, to synthetically boost the property of NCM. Considering that Mo6+ (0.62 Å) could reduce cationic disorder, whose bond energy is stronger than M–O, it contributes greatly to the stabilization of internal structure. What’s more, H3BO3 not only consumes surface residual alkali, but also produces LiBO2 with good ionic conductivity, which can promote the migration rate of Li+. Density functional theory (DFT) calculations and first principles elucidated the feasibility of doping-to-coating. In addition, structural evolution implied that the improved cyclic stability is due to the effective inhibition of serious structure evolution in the modified material. The discovery provides a novel thought for further commercialization of NCM.