不同视密度Mn₃O₄对LiMn₂O₄正极材料性能的影响

Effect of Different Apparent Densities of Mn₃O₄ on the Properties of LiMn₂O₄ Cathode Materials

摘要: 以自制不同视密度四氧化三锰作为锰源，将碳酸锂和四氧化三锰用高温固相法合成尖晶石锰酸锂。通过扫描电镜、X射线衍射的方法研究了不同锰酸锂之间形貌和结构的差别，通过电性能测试的方法重点考察了不同视密度四氧化三锰对合成的锰酸锂的首次充放电性能和循环性能的影响。结果表明：锰酸锂的首次充放电比容量与四氧化三锰视密度大小呈正相关，其中视密度为1.93 g/cm³的四氧化三锰合成的锰酸锂首次充放电比容量最高，分别为122.17 mAh/g和116.82 mAh/g，但其循环性能不是最优，50次放电循环保持率为70.75%。视密度为1.34 g/cm³的四氧化三锰合成的锰酸锂其首次充放电比容量为116.13 mAh/g和110.95 mAh/g，略低于前者，但其循环保持率却是最优，可达到77.02%。

Abstract: Spinel LiMn₂O₄ was synthesized by Li₂CO₃ and Mn₃O₄ with different apparent densities by high temperature solid state reaction. Differences of morphology and structure of different LiMn₂O₄ were studied by SEM and XRD, the effects of different apparent densities of Mn₃O₄ on the first charge-discharge performance and cycle performance of LiMn₂O₄ were investigated by means of electrical performance test. The results show that the first charge-discharge specific capacity of LiMn₂O₄ is positively correlated with the apparent density of Mn₃O₄, the first charge-discharge ca-pacities of LiMn₂O₄ synthesized by Mn₃O₄ with apparent density of 1.93g/cm³ are the highest, 122.17 mAh/g and 116.82 mAh/g respectively, but its cycle performance is not optimal, and the retention rate of 50 cycles is 70.75%. LiMn₂O₄ synthesized by Mn₃O₄ with apparent density of 1.34 g/cm³ has a first charge-discharge capacity of 116.13 mAh/g and 110.95 mAh/g, slightly lower than the former, but its cycle retention rate is the best, reaching 77.02%.