氧化还原
材料科学
过渡金属
X射线光电子能谱
密度泛函理论
阴极
阳离子聚合
化学工程
空位缺陷
电化学
无机化学
氧化物
电极
结晶学
物理化学
化学
催化作用
计算化学
工程类
高分子化学
冶金
生物化学
作者
Qiuyu Shen,Yongchang Liu,Xudong Zhao,Junteng Jin,Yao Wang,Shengwei Li,Ping Li,Xuanhui Qu,Lifang Jiao
标识
DOI:10.1002/adfm.202106923
摘要
Abstract Triggering the anionic redox chemistry in layered oxide cathodes has emerged as a paradigmatic approach to efficaciously boost the energy density of sodium‐ion batteries. However, their practical applications are still plagued by irreversible lattice oxygen release and deleterious structure distortion. Herein, a novel P2‐Na 0.76 Ca 0.05 [Ni 0.23 □ 0.08 Mn 0.69 ]O 2 cathode material featuring joint cationic and anionic redox activities, where native vacancies are produced in the transition‐metal (TM) layers and Ca ions are riveted in the Na layers, is developed. Random vacancies in the TM sites induce the emergence of nonbonding O 2p orbitals to activate anionic redox, which is confirmed by systematic electrochemical measurements, ex situ X‐ray photoelectron spectroscopy, in situ X‐ray diffraction, and density functional theory computations. Benefiting from the pinned Ca ions in the Na sites, a robust layered structure with the suppressed P2‐O2 phase transition and enhanced anionic redox reversibility upon charge/discharge is achieved. Therefore, the electrode displays exceptional rate capability (153.9 mA h g −1 at 0.1 C with 74.6 mA h g −1 at 20 C) and improved cycling life (87.1% capacity retention at 0.1 C after 50 cycles). This study provides new opportunities for designing high‐energy‐density and high‐stability layered sodium oxide cathodes by tuning local chemical environments.
科研通智能强力驱动
Strongly Powered by AbleSci AI