Enhanced high-temperature performance of Li-rich layered oxide via surface heterophase coating

• 来源期刊: 能源化学
• 年，卷（期）: 2020,（12）
• 页码范围: 39-47
• 页数: 9页
• 语种: 英文

摘要

Li-rich layered oxides have become one of the most concerned cathode materials for high-energy lithium-ion batteries,but they still suffer from poor cycling stability and detrimental voltage decay,especially at elevated temperature.Herein,we proposed a surface heterophase coating engineering based on amor-phous/crystalline Li3PO4 to address these issues for Li-rich layered oxides via a facile wet chemical method.The heterophase coating layer combines the advantages of physical barrier effect achieved by amorphous Li3PO4 with facilitated Li+ diffusion stemmed from crystalline Li3PO4.Consequently,the mod-ified Li1.2Ni0.2Mn0.6O2 delivers higher initial coulombic efficiency of 92％ with enhanced cycling stability at 55 ℃(192.9 mAh/g after 100 cycles at 1 C).More importantly,the intrinsic voltage decay has been in-hibited as well,i.e.the average potential drop per cycle decreases from 5.96 mV to 2.99 mV.This surface heterophase coating engineering provides an effective strategy to enhance the high-temperature electro-chemical performances of Li-rich layered oxides and guides the direction of surface modification strate-gies for cathode materials in the future.