Superior high-rate cycling performance of LiFePO4/C-PPy composite at 55 degrees C

作者：Yang, Yang; Liao, Xiao Zhen^*; Ma, Zi Feng; Wang, Bao Feng; He, Li; He, Yu Shi

来源：Electrochemistry Communications, 2009, 11(6): 1277-1280.

DOI：10.1016/j.elecom.2009.04.021

• Polypyrrole coating
• LiFePO4/C cathode
• Lithium ion batteries

A facile chemical polymerization method was applied to prepare LiFePO4/C-PPy composite using Fe(III)tosylate as oxidant. The as-prepared LiFePO4/C-PPy sample with My content of approximately 4 wt% showed great rate capability with a discharge capacity of 115 mAh/g at 20C. High temperate cycling performance of the LiFePO4/C-PPy sample was compared with bare LiFePO4/C at 5C charge-discharge rate at 55 degrees C. The LiFePO4/C-PPy cathode showed superior cycling stability with an initial capacity of 155 mAh/g. Ninety percentage of this initial capacity was retained after 300 cycles, compared to 40% of that of bare LiFePO4/C. The LiFePO4/C-PPy electrode showed stable discharge plateau voltage of 3.35-3.25 V vs. Li+/Li during long term cycling. The superior performance of the LiFePO4/C-PPy electrode was due to the enhanced electrical conductivity, negligible iron dissolution and alleviated electrode cracking contributed by PPy coating.

• 出版日期2009-6
• 单位上海电力大学; 上海交通大学