金属离子掺杂对LiFePO_4结构和性能的影响

Influence of doping different metallic ions on performance of LiFePO_4 material

通过高温固相法,以金属氧化物(TiO2,V2O5,Nb2O5)作前驱体,合成了不同金属离子掺杂的LiFePO4/C复合材料。对以LiFePO4/C为正极的电池进行(XRD)、循环伏安和恒流充放电测试。结果表明,LiNb0.05Fe0.95PO4/C的电化学性能最好,0.05 C倍率下首次放电比容量达到154 mAh/g,即使在1 C倍率下放电,经过60次循环依然能保持在117 mAh/g左右。Fe位掺杂的效果与掺杂离子的半径、价态有密切关系,半径与Fe离子接近、价态高的离子对提高LiFePO4的电化学性能有利。

In this paper,LiFePO4/C composite material doped with different metallic oxides（TiO2,V2O5,Nb2O5） was synthesized by solid-state method.The LiFePO4/C samples were characterized by XRD,CV and electrochemical charge/discharge tests.The results indicate that LiNb0.05Fe0.95PO4/C samples have an initial capacity of 154 mAh/g at 0.05 C,and they are capable of delivering reversible capacities of about 117 mAh/g even at 1 C discharge rate.The LiFePO4/C material doped with ions of similar radius with Fe2＋ and higher valence shows better electrochemical performance.