魔角纺纱
电子顺磁共振
堆积
结构稳定性
电化学
化学
磁滞
锂(药物)
氧化还原
结晶学
过渡金属
氧气
化学物理
金属
结构变化
材料科学
无机化学
核磁共振波谱
物理化学
电极
立体化学
核磁共振
催化作用
凝聚态物理
宏观经济学
内分泌学
工程类
经济
有机化学
物理
医学
冶金
结构工程
生物化学
作者
Hui Liu,Chong Zhao,Qing Qiu,Bei Hu,Fushan Geng,Jingxin Li,Wei Tong,Bingwen Hu,Chao Li
标识
DOI:10.1021/acs.jpclett.1c02185
摘要
Herein, the structure–electrochemistry relationship of O2-Li5/6(Li0.2Ni0.2Mn0.6)O2 is deliberately studied by local-structure probes including site-sensitive 7Li pj-MATPASS NMR, quantitative 6Li magic-angle spinning NMR, and electron paramagnetic resonance (EPR). The extraction and reinsertion of LiTM (Li in the transition metal layer) during the first cycle are only partially reversible, bringing about the formation of tetrahedral LiLi (Li in the Li layer) that can be reversibly (de)intercalated after the activation cycle. The high-voltage oxygen redox process is preserved beyond the first cycle, further manifesting the structural superiority of O2 stacking over O3 stacking in bolstering oxygen redox. Moreover, the (de)lithiation process is highly reversible without pronounced structural hysteresis after the rearrangement of Li and transition metal upon the activation cycle, which can explain well the variation of voltage hysteresis from the first cycle to second cycle. These insights elucidate the imperfect structural stability of O2-type Li-rich layered oxides, which could be further improved by streamlining the returning path of LiTM.
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