Hierarchically-structured nanocrystalline lithium rich layered composites with enhanced rate performances for lithium ion battery

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• 作者：Yi-Chun Jin ^{s9931512@m99.nthu.edu.tw} ; Jenq-Gong Duh ; ^{jgd@mx.nthu.edu.tw}
• 关键词：Hierarchically-structured ; Flake-like ; Li-rich layered composite ; Cathode material ; Lithium ion battery
• 刊名：Energy Storage Materials
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：6
• 期：Complete
• 页码：157-163
• 全文大小：2165 K
• 卷排序：6

文摘

Li-rich layered composite cathode material: 1/2Li2MnO3∙1/2LiMn1/2Ni1/2O2 with a hierarchically-structured flake morphology is firstly synthesized with a solvent-controlled organic route. X-ray diffraction evidences a pure lithium-rich layered phase of as-fabricated materials. Transmission electron microscopy investigated that each single flake possesses a highly crystalline nature and it composed by numerous hierarchically-structured plates around 20 nm. Electrochemical performances demonstrates that flake cathode delivered a significantly enhanced rate capability as compared to conventional particles prepared by regular co-precipitation method. The specific capacity of flakes cycled at 0.1 and 1 C were 210 and 155 mAh/g, respectively. Cyclic voltammetry represents distinct intercalation mechanisms between two samples, in which a higher lithium diffusivity is derived by flakes with respect to particle ones. Electrochemical impedance profiles shows that the charge-transfer resistances of flake cathodes could be effectively suppressed with respect to particles after cycled at elevated discharge rates. This study provides an alternative approach for synthesizing morphologically-tailored Li-rich layered cathode and virtually proves the ability to tolerant high current input and can preserve a good cycling retention.