Ti^(4+)掺杂对磷酸钒锂材料结构和电化学性能的影响

Effect of Ti^(4+)Doping on the Structure and Electrochemical Performances of Li_3V_2( PO_4)_3

分别采用溶胶-凝胶法和高温固相法制备锂离子电池正极材料Li_3V_(1.93)Ti_(0.05)(PO_4)_3/C,研究Ti^(4+)掺杂对Li_3V_2(PO_4)_3材料结构、形貌和电化学性能的影响。结果表明:利用溶胶-凝胶法和高温固相法均得到单斜晶系结构,且无杂相存在,少量Ti^(4+)掺杂并未影响材料的结构形貌,但显著改善了电化学性能。溶胶-凝胶法掺杂Ti^(4+)试样在0.2 C和12 C放电比容量分别为129 m Ah·g^(-1)和102 m Ah·g^(-1),明显高于高温固相法掺杂Ti^(4+)试样,且循环性能良好。研究表明利用溶胶-凝胶法掺杂是一种改善离子掺杂效果的有效路径。

Cathode material Li_3V_(1.93)Ti_(0.05)(PO_4)_3/ C of lithium-ion batteries with Ti^(4+)doped were prepared by sol-gel method and high temperature solid-state method. The effects of doping Ti^(4+)on the structure,morphology and electrochemical performances of Li_3V_2( PO_4)_3were investigated. The results show that Li_3V_(1.93)Ti_(0.05)(PO_4)_3/ C prepared by the two methods has monoclinic systems and purity phases,and it doesn't affect the structure and morphology of the material after doping a little Ti^(4+),but it dramatically improves the electrochemical performances. The sample of doped Ti^(4+)with sol-gel method has perfect cycle performance,and the discharge capacities have reached 129 m Ah·g^(- 1)and 102 m Ah·g^(- 1)at 0. 2 C and 12 C,which is obviously higher than the sample of doped Ti^(4+)with solid-state method.This paper provide an effective way to improve the ion doping by sol-gel method.