尖晶石型LiMn1.925Co0.025Ti0.025Sn0.025O4的合成及性能研究

利用高温固相法制备了尖晶石型LiMn2O4、LiMn1．925Co0．075O4、LiMn1．925Co0.0375Ti0.0375O4、LiMn1．925Co0．025Ti0.025Sn0.025O4锂离子电池正极材料，并用XRD、充放电测试、循环伏安、电化学阻抗测试等研究了其结构和电化学性能．结果表明：掺杂样品均为单一尖晶石结构，在0．2C和3．0-4．2V条件下恒流充放电，发现掺杂后材料的循环性能有很大改善，其中LiMn1．925Co0．025Ti0．025Sn0．025O4具有较高的放电容量，50次循环后容量衰仅为7．97％．活性物质在不同的电位下具有不同的电化学特性，电化学阻抗谱明显不同，并对其进行了解释．

Synthesis and electrochemical properties of spinel LiMn1.925Co0.025Ti0.02Sn0.025O4

The cathode material of Li-ion battery of spinel LiMn2O4 ,LiMn1.925Co0.075O4 ,LiMn1.925Co0.0375Ti0.0375O4, LiMn1.925Co0.258Ti0.025Sn0.025O4 is synthesized by high temperature solid phase method. The structures and electrochemical properties are measured by XRD, charge-discharge at constant current, cyclic voltammetry and AC impedance methods. The results reveal that all the samples exhibit single spinel structure. Under the condition of 0. 2C and 3.0 -4.2V, charge and discharge is carried out galvanostaieally. The results show that the cycle performanee of the doped materials has been greatly improved. Among them LiMn1.925Co0.25Ti0.025Sn0.025O4 has higher discharge capacity and the capacity fading rates are 7.97% after 50 cycles. The active material has different characteristics at different potential, and the AC impedance spectrum is obviously different. And an explanation is made.