Multifunctional ZnO/graphene co-coating on LiNi0.5Co0.2Mn0.3O2 cathode material for improving high voltage electrochemical performances

Layered nickel-rich LiNixCoyMn1-x-yO2 (NCM, x >= 0.5) is considered a promising cathode material for lithium-ion batteries (LIBs) with high energy density. However, the cycling stability and rate capability of the material degrades due to lattice distortion and phase change upon operating at high voltage. In this work, the surface cocoated with ZnO/graphene successfully enhanced the electrochemical performances of cathode material at high voltage ranges. As a result, the co-coating layer accelerates the diffusion of lithium ions, promoting electron migration, suppressing the side reaction between electrodes and electrolytes, and structural deterioration. The co-coating sample had a higher discharge capacity of 185.8 mAh g-1 and retention rate of 90.8% than those of the pristine (166.7 mAh g-1 and 82.4 %) after 200 cycles at 1 C (1C = 180 mAh g-1) at high voltage range.