Preparation and electrochemical properties of a LiFePO sub(4)/C composite cathode material by a polymer-pyrolysis-reduction method

• Published in: Electrochimica acta Vol. 56; no. 7; pp. 2941 - 2946
• Main Authors: Yang, Kerun, Lin, Ziji, Hu, Xuebu, Deng, Zhenghua, Suo, Jishuan
• Format: Journal Article
• Language: English
• Published: 01.01.2011
• Subjects: Carbon; Carbon-carbon composites; Charge; Composite materials; Diffraction; Discharge; Electrochemical impedance spectroscopy; Lithium; Particulate composites; Scanning electron microscopy
• DOI: 10.1016/j.electacta.2010.12.093
• ISSN: 0013-4686

A LiFePO sub(4)/C composite was successfully prepared by a polymer-pyrolysis-reduction method, using FePO sub(4) times 2H sub(2)O and lithium polyacrylate (PAALi) as raw materials. The structure of the LiFePO sub(4)/C composites was investigated by X-ray diffraction (XRD). The micromorphology of the precursor and LiFePO sub(4)/C powders was observed using scanning electron microscopy (SEM), and the in situ coating of carbon on the particles was observed by transmission electron microscopy (TEM). Furthermore, the electrochemical properties were evaluated by cyclic voltammograms (CVs), electrochemical impedance spectra (EIS) and constant current charge/discharge cycling tests. The results showed that the sample synthesized at 700 degree C had the best electrochemical performance, exhibiting initial discharge capacities of 157, 139 and 109 mAh g super(-1) at rates of 0.1, 1 and 5 C, respectively. Moreover, the sample presented excellent capacity retention as there was no significant capacity fade after 50 cycles.