混合铁源合成锂离子电池正极材料LiFePO_4/C

Preparing carbon coated lithium ferrous phosphate for cathode material for lithium ion battery using mixed iron sources

以Fe2O3和Fe C2O4·2 H2O（摩尔比1∶1）为混合铁源,柠檬酸为碳源,通过高温固相法合成了锂离子电池正极材料Li Fe PO4/C。采用X射线衍射光谱法（XRD）、恒电流充放电测试、循环伏安（CV）和交流阻抗谱（EIS）对材料的物相结构和电化学性能进行了表征。通过与单一铁源（Fe2O3和Fe C2O4·2 H2O）合成Li Fe PO4/C进行比较,表明混合铁源合成的材料具有较好的电化学性能。在4.2～2.4 V充放电,0.1 C首次放电比容量为142.1 m Ah/g,循环50次后达到131.5m Ah/g,容量保持率为92.54%,高于单一铁源合成的材料;在0.2 C、0.5 C、1 C和2 C的倍率循环性能测试也表明混合铁源合成的材料有较好的电化学性能。

Carbon coated lithium ferrous phosphate （LiFePO4/C） as cathode material of Li-ion battery was synthesized by solid state reaction method with Fe2O3 and Fe C2O4·2 H2O （molar ratio 1 ： 1） for mixed iron source and citric acid as carbon source.The crystal structure and the electrochemical performance were characterized by XRD, charge- discharge testing,cyclic voltammetry （CV） and electrochemical impedance spectra（EIS）.Compared with the compo- sites synthesized by the single iron source, the composites （using mixed iron source） has better electrochemical performance,and when charged-discharged at 4.2-2.4 V, the initial specific discharge capacity at the 0.1 C is 142.1 mAh/g, and the specific discharge capacity remains 131.5 mAh/g with the capacity retention of 92.54% after 50 cycles. When charged-discharged at 0.2 C, 0.5 C, 1 C and 2 C, the composites also has better electrochemical performance.