Enhancing surface and internal structural stability of LiNi0.8Co0.1Mn0.1O2 by yttrium phosphate dual effects

Abstract

YPO4 modified Ni-rich cathode materials LiNi0.8Co0.1Mn0.1O2 (NCM811) are favourably synthesized via a traditional high temperature solid-state method. Herein, the structure as well as thermal stability are promoted through the synergistic effect of Y3+ doping and LiYO2- Li3PO4 dual surface modification. The results turn out to solve the lattice structure defects, Li+ migration issue and, most of all, residual lithium issue. The most effective sample exhibits extraordinary 96.35% capacity retention with the initial specific discharge capacity of 186.1 mAh g−1 at 4.4 V cut-off voltage, 1 C, 25 ℃ after 100 cycles. Moreover, after 0.5, 1, 2, 4, 8 C cycling periods, at the time when the rate back to 0.5 C, the capacity of the YPO4 modified samples remain almost the same as the first 0.5 C cycles. It obviously can be seen that the YPO4 modification in this work is no doubt a promising strategy to optimize the manufacturing of cathode materials in Li-ion batteries field.