High-rate performance of xLiFePO4¡¤yLi3V2(PO4)3/C composite cathode materials synthesized via polyol process
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- 作者：Chao Gao ; Heng Liu ; h_liu@scu.edu.cn ; Guobiao Liu ; Jun Zhang ; Wei Wang
- 关键词：xLiFePO4· ; yLi3V2(PO4)3/C ; Polyol process ; Cathode materials ; Lithium ion battery
- 刊名：Materials Science and Engineering: B
- 出版年：2013
- 出版时间：1 March, 2013
- 年：2013
- 卷：178
- 期：4
- 页码：272-276
- 全文大小：902 K
文摘
xLiFePO4¡¤yLi3V2(PO4)3/C composite cathode materials were synthesized via a polyol process, using LiOH¡¤H2O, Fe3(PO4)2¡¤8H2O, V2O5 and H3PO4 as raw materials, citric acid and PEG as carbon sources, and TEG as both a solvent and a reductant. Structural and morphological characterizations of as-prepared materials were carried out by X-ray diffraction (XRD) as well as scanning electron microscopy (SEM), respectively. Furthermore, electrochemical properties of as-prepared materials were analyzed by charge-discharge tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). XRD results indicated that the composites consisting of an olivine phase of LiFePO4 and a monoclinic phase of Li3V2(PO4)3 are well-crystallized. It is found that the LF0.6P¡¤LV0.4P/C composite exhibited better electrochemical performance than pristine LFP/C and LVP/C at 5 C and 10 C rate and delivered 126 mAh g?1 and 110 mAh g?1, respectively. The favorable particles morphology with less than 100 nm size and low extent agglomeration is believed as a factor. In addition, the co-existence of V3+-doped LiFePO4/C and Fe2+-doped Li3V2(PO4)3/C was supposed as another reason.