(1. 湘潭大学 化学学院 环境友好化学与应用教育部重点实验室,湘潭 411105;
2. 湖南石油化工职业技术学院,岳阳 414012)
摘 要: 采用改进的固相反应法合成了高性能的锂离子电池正极材料LiMn2O4。首先,以廉价的MnSO4为原料,通过水解−氧化法制备纳米级Mn3O4前驱体;然后,将Mn3O4和Li2CO3混合均匀,在750 ℃固相反应20 h,得到尖晶石型LiMn2O4。用X射线衍射(XRD)和扫描电镜(SEM)对Mn3O4前驱体和LiMn2O4样品进行表征,用充放电测试和循环伏安技术对LiMn2O4样品进行电化学性能研究。结果表明:所制备的LiMn2O4具有完整的尖晶石型结构,且晶体粒子分布均匀。所制备的LiMn2O4材料在3.0~4.4 V之间,室温(25 ℃)下,在0.2C倍率下首次放电比容量为130.6 mA∙h/g;在0.5C倍率下首次放电比容量为127.1 mA∙h/g,30次循环后,容量仍有109.5 mA∙h/g,且样品具有较好的高温性能。
关键字: 锂离子电池;正极材料;尖晶石LiMn2O4;水解−氧化法;Mn3O4前驱体
(1. School of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Applications,
Ministry of Education, Xiangtan University, Xiangtan 411105, China;
2. Hunan Petrochemical Vocational Technology College, Yueyang 414012, China)
Abstract:LiMn2O4 with high-performance for the application of lithium-ion batteries was successfully synthesized by a modified solid phase reaction route. First, the precursor Mn3O4 was prepared by a hydrolyzation -oxidation method using cheap MnSO4 as Mn source. Then, the as-prepared precursor Mn3O4 and Li2CO3 were mixed homogeneously and calcined at 750 ℃ for 20 h to obtain spinel LiMn2O4. The properties of samples were characterized by XRD and SEM, charge-discharge tests and cyclic voltammetry. The results show that the as-prepared LiMn2O4 has spine structure and exhibits uniform particle size distribution. The initial discharge capacities of the as-prepared LiMn2O4 are as high as 130.9 mA∙h/g at 0.2C and 127.1 mA∙h/g at 0.5C in the voltage range of 3.0−4.4 V at 25 ℃, especially, the discharge capacity at 30th cycle still keep to be 109.5 mA∙h/g at 0.5C. Besides, the as-prepared LiMn2O4 presents good high temperature performance.
Key words: lithium ion battery; cathode material; spinel LiMn2O4; hydrolyzation-oxidation method; Mn3O4 precursor