氧化还原
材料科学
离域电子
电化学
阴极
化学物理
化学工程
氧气
电子结构
电极
纳米技术
物理化学
化学
计算化学
有机化学
工程类
冶金
作者
Xianggang Gao,Haiyan Zhang,Shihao Li,Shuai Zhang,Chaohong Guan,Xiao Hu,Juanlang Guo,Yanqing Lai,Zhian Zhang
标识
DOI:10.1002/adfm.202304065
摘要
Abstract Anionic and cationic redox chemistries boost ultrahigh specific capacities of Li‐rich Mn‐based oxides cathodes (LRMO). However, irreversible oxygen evolution and sluggish kinetics result in continuous capacity decay and poor rate performance, restricting the commercial fast‐charging cathodes application for lithium ion batteries. Herein, the local electronic structure of LRMO is appropriately modulated to alleviate oxygen release, enhance anionic redox reversibility, and facilitate Li + diffusion via facile surface defect engineering. Concretely, oxygen vacancies integrated on the surface of LRMO reduce the density of states of O 2p band and trigger much delocalized electrons to distribute around the transition metal, resulting in less oxygen release, enhancing reversible anionic redox and the MnO 6 octahedral distortion. Besides, partially reduced Mn and lattice vacancies synchronously stimulate the electrochemical activity and boost the electronic conductivity, Li + diffusion rate, and fast charge transfer. Therefore, the modified LRMO exhibits enhanced cyclic stability and fast‐charging capability: a high discharging capacity of 212.6 mAh·g −1 with 86.98% capacity retention after 100 cycles at 1 C is obtained and to charge to its 80%, SOC is shortened to 9.4 min at 5 C charging rate. This work will draw attention to boosting the fast‐charging capability of LRMO via the local electronic structure modulation.
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