铝掺杂磷酸钒锂的制备及电化学性能研究

Synthesis and Electrochemical Properties of Aluminum Doped Lithium Vanadium Phosphate

针对磷酸钒锂电导率低的问题,以硝酸锂、偏钒酸铵、磷酸二氢铵为原料,甘氨酸为络合剂和燃料,葡萄糖为碳源,硝酸铝为铝源,采用溶液燃烧合成法制备铝掺杂的Li_3V_2(PO_4)_3/C粉末,以改善其电化学性能。将制备得到的铝掺杂的Li_3V_2(PO_4)_3/C粉末作为锂离子电池正极材组装成电池进行了恒电流充放电测试、循环伏安(CV)和交流阻抗(EIS)等电化学性能测试。结果表明:铝掺杂能有效提高磷酸钒锂电导率,不同的铝掺杂比例的磷酸钒锂具有不同的的电子电导率和锂离子扩散速率,从而具有不同的放电比容量、循环性能和倍率性能;当铝掺杂含量为1%时,磷酸钒锂具有最优的电化学性能,在充放电速度为10C循环500次后放电容量为104.6 mAh/g。

To improve the low conductivity of lithium vanadium phosphate,aluminum doped Li3V2(P04)3/C powder was prepared by solution combustion synthesis using lithium nitrate,ammonium metavanadate and ammonium dihydrogen phosphate as raw materials,glycine as complexing agent and fuel,glucose as carbon source and aluminum nitrate as aluminum source Respectively. The electrochemical performances of the as-prepared aluminum doped Li3V2(PO4)3/C powder as cathode material for lithium ion battery were characterized by constant current charge-discharge,cyclic voltammetry (CV) and AC impedance (EIS). The results show that aluminum doping can effectively improve the conductivity of lithium vanadium phosphate. Different aluminumdoped proportions of lithium vanadium phosphate have different electron conductivities and diffusion rates of lithium ion. When the doping content of aluminum is 1%,the lithium vanadium phosphate has the optimum electrochemical performances with the discharge capacity of 104.6 mAh/g at the rate of 10 C after 500 cycles.