Unveiling the Evolution of LiCoO 2 beyond 4.6 V

作者：Zixin Wu, Guifan Zeng, Jianhua Yin, Chao‐Lung Chiang, Qinghua Zhang, Baodan Zhang, Jianken Chen, Yawen Yan, Yonglin Tang, Haitang Zhang, Shiyuan Zhou, Qingsong Wang, Xiaoxiao Kuai, Yan‐Gu Lin, Lin Gu, Yu Qiao, Shi‐Gang Sun · 发表于：ACS Energy Letters · 年份：2023 · DOI：10.1021/acsenergylett.3c01954 · 被引用次数：153 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Supercapacitor Materials and Fabrication

The working mechanism of LiCoO 2 beyond 4.6 V presents complicated issues: (1) the ambiguous multistructural evolutions, (2) the vague O-related anionic redox reactions (ARR) triggered by the overlap Co–O bands, and (3) the serious electrode–electrolyte interface stability challenges. The intricate relationship among them turns into a classic “chicken and egg” conundrum, leading to a confusing evolution process of LiCoO 2 . Herein, from an ingenious perspective combining stacking faults and nonhomogeneous delithiation, we originally demonstrate a series of intergrowth phase evolutions from O3 to O1, passing through the so-called H1-3 phase. Moreover, in sharp contrast to the O–O dimer formed in a traditional Li-rich layered cathode, a moderate and stable arrangement of oxidized lattice oxygen is unveiled as a manifestation of ARR in LiCoO 2 . Additionally, we clarify the nature that dehydrogenation and hydrolysis of electrolyte trigger the chain decompositions and intensify the surface degradation.