The challenge of commercial layered-structure nickel-rich cathodes in lithium-ion batteries (LIBs) are the rapid capacity/voltage degradation at high rate capability and thermal runaway. The wide operational voltage range and excellent electrochemical stability of the coating material are key points to improve electrochemical performance and thermal stability at high voltage and high rate conditions. The uniformly olivine-type LiCoPO (LCP) coatings were successfully prepared on the surface of LiNiCoMnO (NCM811) cathode combining sol–gel method and heat treatment. The capacity retention and operating voltage stability of the cathode at high cutoff voltage of 4.6 V were dramatically improved due to the ultrathin and stable interface is designed. The modified NCM811 exhibited a high cycling capacity of 157.7 mAh·g at 5 C with a capacity loss of only 12.1 %. In high nickel cathode coating modification, LCP as the thinnest phosphate coating effectively improves the capacity decay of the cathode at high rate. The interface reconstruction provided a stable channel of Li transport, which suppressed the cathode/electrolyte interface reaction to enhance the stability. The formation of strong covalent PO bonds at the interface significantly reduced the oxidizing activity on the NCM811 surface, further inhibiting the oxygen release and irreversible phase transition.

中文翻译：

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通过构建超薄LiCoPO4涂层增强高镍正极的高电压电化学稳定性

锂离子电池（LIB）中商用层状结构富镍阴极面临的挑战是高倍率性能和热失控时容量/电压的快速下降。涂层材料宽的工作电压范围和优异的电化学稳定性是提高高电压、高倍率条件下电化学性能和热稳定性的关键。结合溶胶凝胶法和热处理，在LiNiCoMnO（NCM811）正极表面成功制备了均匀的橄榄石型LiCoPO（LCP）涂层。由于超薄且稳定的界面设计，正极在4.6 V高截止电压下的容量保持率和工作电压稳定性得到显着提高。改进后的NCM811在5 C下表现出157.7 mAh·g的高循环容量，容量损失仅为12.1%。在高镍正极涂层改性中，LCP作为最薄的磷酸盐涂层，有效改善正极高倍率下的容量衰减。界面重构提供了稳定的锂传输通道，抑制了正极/电解质界面反应，增强了稳定性。界面处强共价PO键的形成显着降低了NCM811表面的氧化活性，进一步抑制了氧的释放和不可逆相变。