Enhanced high-rate capability and high voltage cycleability of Li2TiO3-coated LiNi0.5Co0.2Mn0.3O2 cathode materials

Abstract

For LiNi_0.5Co_0.2Mn_0.3O₂ materials, poor cycling stability is commonly observed under high-voltage operation (>4.3 V), particularly when accompanied by high-rate operation. Here, layered LiNi_0.5Co_0.2Mn_0.3O₂ was surface-modified by a Li₂TiO₃ coating and investigated during cycling for its high-rate capability as well as at different cutoff voltages. It was found that the Li₂TiO₃ coating effectively improved the battery performance, compared to the bare LiNi_0.5Co_0.2Mn_0.3O₂, which suffered a serious capacity fading on cycling. According to the results of charge/discharge experiments, the 6 wt%-coated sample delivered a high discharge capacity of 181.5 mA h g⁻¹ at a rate of 1C (0.6 mA cm⁻²) under a high cutoff voltage (4.8 V). After 150 cycles, it still retained 69% capacity. This demonstrates that the coating strategy is an effective route to high energy density and high-voltage stable cathode materials for high-performance LIBs.