以Mn3O4为前驱体制备尖晶石型LiMn2O4及其性能

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。

Preparation process and performance of spinel LiMn2O4 using Mn3O4 as precursor

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.