(中南大学 冶金科学与工程学院, 长沙 410083)
摘 要: 采用共沉淀法可以制备出首次放电容量高达210 mA·h/g的LiNi0.5Mn0.5O2材料(2.8~4.5 V, 电流密度30 mA/g), 但材料循环性能受制备过程中的处理工艺影响很大,处理不严格将导致材料循环性能严重下降。 围绕材料的循环性问题, 对其机理进行了分析并在此基础上对制备工艺进行了进一步改善: 分别从配锂方式, 烧结过程中的升降温速率以及烧结的保温制度进行了系统研究。结果表明: 采用改进配锂方式, 缓慢升温速率(2 ℃/min), 高低温结合的烧结制度和快速风冷工艺所制备的材料首次放电容量达到188 mA·h/g, 30个循环后仍保持在174 mA·h/g, 循环效率有了明显的提高。
关键字: LiNi0.5Mn0.5O2; 锂离子电池; 正极材料; 循环性能
cathode material for lithium secondary batteries
(School of Metallurgical Science and Engineering,
Central South University, Changsha 410083, China)
Abstract: LiNi0.5Mn0.5O2 was prepared by co-precipitation methode whose first discharge capicity can achieved 210 mA·h/g(2.8-4.5 V, current density: 30 mA/g). But the material's cycle performance is seriously affected by the synthesis conditions.If the synthesis conditions were not seriously controlled the material's cycle performance would be bad. The inner cause to the cycle performance was studied and the preparation way was reformed. By improving the matched way of lithium, studing the affection of heating and cooling rates on the material and renewing the heat treatment, the material's cycle performance was improved. The material's first discharge capicity can achieve 180 mA·h/g and aft, er 30 cycles the discharge capicity remains 175 mA·h/g.
Key words: LiNi0.5Mn0.5O2; lithium-ion battery; cathode material; cycle performance