Lithium cobalt oxide (LiCoO₂ or LCO) is undoubtedly one of the best commercial cathode materials for Lithium-ion batteries (LIBs). High energy density, excellent cycle life, and long-term reliability make it most attractive for the growing electronics market. The working voltages in LCO have been raised to achieve greater energy density that can fulfill fast charging and portable electronics consumer needs. Yet, charging beyond 4.4 V inevitably decreases the cathode stability, resulting in poor performance. Several factors cause operational issues in LCO at high voltages, particularly surface degradation, unfavorable side reactions, and irreversible phase transitions. These detrimental phenomena are aggravated by the increased charging voltage, leading to rapid capacity decay and early cell failure. Our review summarizes the failure mechanisms and mitigation strategies adopted recently to stabilize LCO at high cutoff voltages. We begin our discussions with the crystal structure analysis of LCO, describe the possible degradation phenomena and modification routes, and finally examine the prospects and challenges of LCO-based research in all-solid-state batteries (ASSBs).

钴酸锂（LiCoO ₂或LCO）无疑是锂离子电池（LIB）的最佳商用正极材料之一。高的能量密度、出色的循环寿命和长期可靠性使其对不断增长的电子市场最具吸引力。LCO 的工作电压已提高，以实现更高的能量密度，从而满足快速充电和便携式电子消费者的需求。然而，充电电压超过 4.4 V 不可避免地会降低阴极稳定性，导致性能不佳。有几个因素会导致 LCO 在高电压下出现运行问题，特别是表面退化、不利的副反应和不可逆的相变。充电电压增加会加剧这些有害现象，导致容量快速衰减和早期电池故障。我们的审查总结了失败机制和最近采用的缓解策略是为了在高截止电压下稳定 LCO。我们从LCO的晶体结构分析开始讨论，描述可能的降解现象和改性路线，最后探讨基于LCO的全固态电池（ASSB）研究的前景和挑战。