Cycle performance improvement of Li-rich layered cathode material Li[Li0.2Mn0.54Ni0.13Co0.13]O2 by ZrO2 coating

Abstract

Lithium-rich layered cathode material Li[Li0.2Mn0.54Ni0.13Co0.13]O2 with spherical morphology is prepared via co-precipitation method followed by high-temperature treatment and surface coated with a uniform nano-layer of ZrO2 by controlled-hydrolysis of Zirconium(IV) Propoxide. The results show that Li[Li0.2Mn0.54Ni0.13Co0.13]O2 with a well-ordered layered structure consists of small and homogenous primary particles ranging from 100nm to 200nm.The ZrO2 layer with nano-sized particles is coated uniformly on the matrix particle surface. A notable improvement of the cathode coated by ZrO2 is obtained in cycle performance from charge–discharge cycling tests in the range of 2.0–4.8V, and the optimum amount of ZrO2 coating which maximizes the capacity retention is 1wt.%. A high initial discharge capacity of 253.1mAh/g at 0.1C is obtained for the 1wt.% ZrO2-coated sample, and it maintains a capacity of 207.3mAh/g after 50cycles at 0.5C and a capacity of 235.3mAh/g after 50cycles at 0.2C. The improved cycling performance of ZrO2-coated Li[Li0.2Mn0.54Ni0.13Co0.13]O2 is attributed to the decrease of electrolyte decomposition reactions and the alleviation of the impedance due to the existence of ZrO2 coating layer.