期刊
ELECTROCHIMICA ACTA
卷 144, 期 -, 页码 22-30出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.electacta.2014.06.155
关键词
Yttrium-doping; layered lithium-rich Cathode Materials; Lithium-Ion Batteries
资金
- National Natural Science Foundation of China [61171008, 21103024]
- Dalian Mingjia Metal Products Co., Ltd
- Shanghai Jubo Energy Technology Co., Ltd
- Dunhuang Libo Technology Co., Ltd
To improve the cycling performance and rate capability of the promising layered lithium-rich cathode materials, we substitute Co3+ in Li[Li0.20Mn0.534Ni0.133 Co-0.133]O-2 with unusually larga Y3+ during coprecipitation and synthesize Li[Li0.20Mn0.534 Ni0.133Co0.133-x Y-x]O-2 (0 <= x <= 0.0665). The influences of yttrium content on the electrochemical properties of the lithium-rich materials are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), galvanostatic charge-discharge tests and electrochemical impedance spectroscopy (EIS) techniques. The charge-discharge cycling tests suggest that after heating at 1223 K in air for 10 h, the material with x = 0.00665 deliver a high discharge capacity of 349.7 mAhg(-1) after 1 cycle and 225.2 mAhg(-1) after 80 cycles with a current rate of 0.1 C between 2.0 and 4.6V vs., Li/Li+. Electrochemical impedance spectroscopy indicates that Li[Li0.20Mn0.534Ni0.133Co0.133-xYx]O-2 electrode has lower impedance during cycling. The higher capacity retention and high-rate capability of yttrium-substituted materials can be ascribed to the expanded Li+ diffusing channels in the layered structure, lower surface film resistance and lower charge transfer resistance of the electrode during cycling. (C) 2014 Published by Elsevier Ltd.
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