Improving storage performance and lattice oxygen stability of single crystal LiNi0.925Co0.03Mn0.045O2 by integrating utilization of surface residual lithium and lattice modulation.

[Display omitted] • Li 3 PO 4 coating reduces the air sensitivity of single crystal Ni-rich cathode materials. • Li 3 PO 4 coating and Mg2+ doping inhibited the formation of oxygen vacancies.. • Magnesium ions modulated the structural parameters of the materials and changed the bond lengths. • A simple strategy to enhance the surface stability of single crystal Ni-rich materials is provided. In lithium-ion batteries, Ni-rich single crystal cathode material (Ni > 90 %) is a promising cathode material, but it has not yet been put into commercial application due to defects such as structural degradation, air sensitivity and thermal instability. In this paper, the residual lithium compounds on the surface of high-nickel materials are not useless. Li 3 PO 4 coated and Mg2+ doped single crystal cathode materials (SC-NCM-MP) were successfully prepared by precisely controlling the amount of MgHPO 4 by titration and reacting with lithium compounds left on the surface of LiNi 0.925 Co 0.03 Mn 0.045 O 2 (SC-NCM) cathode materials. The SC-NCM-MP samples exhibit better lattice oxygen stability, Li-ion mobility, storage performance and electrochemical performance, with a retention of 89.36 % after 100 cycles, which is much higher than 79.78 % of SC-NCM. [ABSTRACT FROM AUTHOR]