Suppressing Interfacial Structure Failure of Ni-Rich Cathode Materials Under High Work Voltage Towards Improved Cycling Stability Enabled Via Li2mno3 Based Surface Construction

Abstract

Layered nickel-rich oxides with high energy density are subject to malignant irreversible phase transition reaction on interface between cathode and electrolyte during high voltage charging/discharging, which leads to their severe electrochemical performance failure. Herein, an effective surface modification strategy was developed to uniformly coat Li2MnO3 on the surface of LiNi0.8Co0.1Mn0.09Al0.01O2（NCMA） using a co-precipitation assisted high temperature solid phase method. Benefits from the high voltage (below 4.5 V) stability of Li2MnO3 based surface improved the structural stability of LiNi0.8Co0.1Mn0.09Al0.01O2 and the cycling performance at high cut-off voltages significantly. As optimal condition, 5 wt.% Li2MnO3 modified NCMA (5%-M-NCMA) shows the best electrochemical performance whit 215.06 and 224.30 mAh g-1 of initial discharge specific capacities at high voltage rages of (3.0 - 4.5 V) and (3.0 - 4.8 V) at 0.1 C, respectively. Under the reinforcement of the high voltage stable table interface, the capacity retention of the modified materials after 200 cycles at a rate of 1 C is 83.89 and 78.09% under 4.5 and 4.8 V, which were improved relative by 8.39% and 32.75% relative to the uncoated samples.

Keywords: Nickel-rich cathode materials, LiNi0.8Co0.1Mn0.09Al0.01O2, High voltage stability, Mn3O4, Li2MnO3