材料科学
阴极
氧化物
电化学
相(物质)
化学工程
表面改性
过渡金属
透射电子显微镜
表层
插层(化学)
动力学
电极
离子
扩散
图层(电子)
纳米技术
无机化学
物理化学
冶金
化学
热力学
工程类
物理
催化作用
有机化学
生物化学
量子力学
作者
Qinglu Fan,Mateusz Zuba,Yanxu Zong,Ashok S. Menon,Anthony T. Pacileo,Louis F. J. Piper,Guangwen Zhou,Hao Liu
标识
DOI:10.1021/acsami.2c09937
摘要
The surface of the layered transition metal oxide cathode plays an important role in its function and degradation. Modification of the surface structure and chemistry is often necessary to overcome the debilitating effect of the native surface. Here, we employ a chemical reduction method using CaI2 to modify the native surface of single-crystalline layered transition metal oxide cathode particles. High-resolution transmission electron microscopy shows the formation of a conformal cubic phase at the particle surface, where the outmost layer is enriched with Ca. The modified surface significantly improves the long-term capacity retention at low rates of cycling, yet the rate capability is compromised by the impeded interfacial kinetics at high voltages. The lack of oxygen vacancy generation in the chemically induced surface phase transformation likely results in a dense surface layer that accounts for the improved electrochemical stability and impeded Li-ion diffusion. This work highlights the strong dependence of the electrode's (electro)chemical stability and intercalation kinetics on the surface structure and chemistry, which can be further tailored by the chemical reduction method.
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