Cr3+掺杂LiNi0.5Mn1.5O4材料的制备及性能研究

采用高温固相法合成了Cr₃₊掺杂的LiNi_0.5Mn_1.5O₄正极材料,研究了掺杂量对材料物理性能和电化学性能的影响。利用XRD、SEM对材料的结构和形貌进行了表征,结果显示样品具有棱边清晰的尖晶石形貌。讨论了不同Cr₃₊掺杂量对LiCr_xNi_0.5-0.5xMn_1.5-0.5xO₄(x=0,0.05,0.1,0.15,0.2)正极材料性能的影响。充放电测试、循环伏安和交流阻抗测试结果表明：当Cr₃₊的掺杂量为x=0.1时(LiCr_0.1Ni_0.45Mn_1.45O₄)正极材料的性能最好,0.1C、0.5C、1C、2C及5C的首次放电比容量依次为131.54mAh g_-1、126.84mAh g_-1、121.28mAh g_-1、116.49mAh g_-1和96.82mAh g_-1,1C倍率下循环50次,容量保持率仍为96.5%。

Synthesis and performance study of Cr-doped LiNi0.5Mn1.5O4 cathode material

The Cr₃₊ doped LiNi_0.5Mn_1.5O₄ cathode materials were successfully synthesized by solid-state method and the effect of doping amount into cathode material on its physical and electrochemical properties was studied. With the structure and morphology of cathode material characterized by X-ray diffraction and SEM, the results showed that the sample exhibited a pure spinel crystal structure. The effect of different Cr₃₊ doping amounts on the properties of LiCr_xNi_0.5-0.5xMn_1.5-1.5xO₄(x=0, 0.05, 0.1, 0.15, 0.2)cathode materials was discussed. The results of galvanostatic charge-discharge, CV and EIS test suggested that electrochemical properties of LiCr_0.1Ni_0.45Mn_1.45O₄ is the best when the Cr₃₊ doping amount is 0.1. At discharge rates of 0.1, 0.5, 1, 2, and 5C with the first specific capacities of 131.54, 126.84, 121.28,116.49 and 96.82mAh g_-1 respectively. At 1C rate after 50 cycles, its specific discharge capacity retention rate is 96.5%.