材料科学
法拉第效率
阴极
离子
降级(电信)
锂(药物)
氧化物
上部结构
结晶学
电极
化学工程
阳极
冶金
物理化学
热力学
化学
物理
工程类
电信
内分泌学
医学
有机化学
计算机科学
作者
Zhibo Li,Yiwei Li,Mingjian Zhang,Zu‐Wei Yin,Liang Yin,Shenyang Xu,Changjian Zuo,Rui Qi,Haoyu Xue,Jiangtao Hu,Bo Cao,Mihai Chu,Wenguang Zhao,Yang Ren,Lin Xie,Guoxi Ren,Feng Pan
标识
DOI:10.1002/aenm.202101962
摘要
Abstract As one of the most promising cathodes for Li‐ion batteries, Li‐rich layered oxides suffer from low Coulombic efficiency, severe capacity fading, and voltage decay, which are related to the aggregated Li@Mn 6 superstructure units. Herein, a Co‐free Li‐rich oxide Li[Li 1/4 Mn 1/2 Ni 1/6 Al 1/12 ]O 2 through Al substitution of Co in Li[Li 1/4 Mn 1/2 Ni 1/6 Co 1/12 ]O 2 , is designed. Combining the average structural refinement with the detailed local structural/chemical analysis, it is found that the introduced Al ions occupy the Mn sites in Li@Mn 6 superstructure units, which further induces the partial replacement of the central Li ions in Li@Mn 6 units by Ni 2+ . The modified superstructure units stabilize the anionic framework and suppress structural degradation during long‐term cycling. A superior cyclability (a capacity retention of 91.4% after 500 cycles at 1 C) is achieved. This work not only deepens the understanding into the mechanism of Al substitution, but also provides a novel route to design high‐performance Li‐rich cathodes by modifying the local functional units.
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