结构稳定性
阳离子聚合
电化学
离子
晶体结构
阴极
材料科学
兴奋剂
相(物质)
化学
无机化学
化学工程
结晶学
工程类
高分子化学
结构工程
电极
物理化学
有机化学
光电子学
作者
Chunliu Xu,Wei Xiang,Zhenguo Wu,Lang Qiu,Yong Ming,Wen Yang,Luchao Yue,Jun Zhang,Benhe Zhong,Xiaodong Guo,Gongke Wang,Yuxia Liu
标识
DOI:10.1016/j.cej.2020.126314
摘要
The cationic ordering of Ni-rich cathode materials at original state and in lithiation/delithiation process is the key factor in obtaining high discharge capacity and excellent cycle performance. However, it is still one of the greatest challenges to synthesize Ni-rich cathodes with low cationic disordering and maintain the well-ordered layered structure with no phase degradation during cycling. Herein, cationic ordering tuned Ni-rich cathodes with well-ordered layered structure at as-prepared state and suppressed cationic mixing during cycling are synthesized by synchronous dual-site doping of Zn2+ at transition metal (TM) and lithium sites. The proper amount of Zn2+ ions doped at TM sites reduce the content of Ni2+, thus promoting the ordering of layered structure in as-prepared state and ensuring high capacity. Meanwhile, a part of Zn2+ ions substituted for Li+ ions act as pillaring ions, inhibiting the migration of TM ions from TM slabs to Li slabs and maintaining the integrity of crystal structure during lithiation, especially at highly delithiated state. The first principle calculations demonstrate that the dual-site doping of Zn2+ in Ni-rich cathode is thermodynamically favorable and the modified cathodes have excellent structure and phase stability during electrochemical reaction. With the tuned cationic ordering, Zn modified cathode shows high capacity and stable cyclability, with significantly improved capacity retention of 86% at 5C over 200 cycles and excellent high-temperature performance.
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