期刊
ELECTROCHIMICA ACTA
卷 127, 期 -, 页码 259-265出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.electacta.2014.02.037
关键词
lithium-rich layered oxide; cathode material; grain boundary; cyclic stability; rate capability
资金
- National Natural Science Foundation of China
- National Natural Science Foundation [21273084]
- Natural Science Fund of Guangdong Province [10351063101000001]
- key project of Science and Technology in Guangdong Province [2012A010702003]
- Natural Science Foundation of Guangdong Province [U1134002]
A novel method, self-directed chemical method, is proposed to synthesize lithium-rich layered oxide Li[Li0.2Ni0.2Mn0.6]O-2 as cathode of lithium ion batteries with improved rate capability. In this method, Li2CO3 powder that has low dissolvability in aqueous solution is introduced as precipitating agent to induce the formation of transition-metal carbonate, resulting in the precursor Ni0.25Mn0.75CO3 with a hierarchical structure: secondary particles assembled with interconnected primary particles. This hierarchical structure remains in subsequent product (Li[Li0.2Ni0.2Mn0.6]O-2-T). Electrochemical measurements indicates that Li[Lia(2)Ni(0.2)Mn(0.6)]O-2-T delivers a capacity of 222 mAhg(-1) at 1st cycle (0.05C, 1C= 263 mAhg(-1)) and holds 207 mAh g(-1) at 50th cycle, which is slightly better than the sample from a traditional co-precipitation method (Li[Li0.2Ni0.2Mn0.6]O-2-L). More importantly, Li[Li0.2Ni0.2Mn0.6]O-2-T is able to stably offer 156 mAh g(-1) at 0.5C, 136 mAh g(-1) at 1C and 108 mAhg(-1) at 2C, much better than Li[Li0.2Ni0.2Mn0.6]O-2-L. The improved performance is attributed to the tightly interconnected structure and smaller particle size, which facilitates the diffusion of Li ions in the material bulk and reduces the barrier of charge transfer reaction. (C) 2014 Elsevier Ltd. All rights reserved.
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