壳聚糖单体溶胶-凝胶煅烧合成LiFePO4_/C正极

Synthesis of LiFePO_4/C Cathode by Sol-Gel and Calcining Method with Chitosan Monomer

本文以壳聚糖单体为碳源兼凝胶剂,利用溶胶-凝胶煅烧合成了锂离子电池LiFePO4/C正极材料.使用XRD和SEM对合成的材料进行表征,用恒电流充放电测试了LiFePO4/C电极的电化学性能.当壳聚糖单体与LiFePO4摩尔比为1:1.2时,600℃煅烧的LiFePO4/C电极性能最佳,其粒径分布均匀(200～400 nm),该电极0.2C倍率放电比容量为155 mAh.g-1,30周期循环放电比容量仍保持152 mAh.g-1,库仑效率为97.9%.

The LiFePO4/C cathode materials for Li-ion battery were synthesized by sol-gel and calcining method using chitosan monomer as a carbon source and a gelating agent. The structures and morphologies were characterized by X-ray diffraction spec- troscopy （XRD） and scanning electron microscopy （SEM）. The electrochemical performance was investigated by the galvanostatic charge-discharge test. When the molar ratios between chitosan monomer and LiFePO4 were 1：1.2, the LiFePO4/C cathode calcined at 600 ℃ showed the best performance. The particle sizes ranged 200 - 400 nm. The initial discharge capacity of 155 mAh·g^-1 was achieved at room temperature with discharge rate of 0.2C, while the capacity of 152 mAh ·g^-1 could be maintained after 30 charge-discharge cycles. The coulombic efficiency was 97.9%. Key words： chitosan; LiFePOJC; sol-gel method; Li-ion battery