锂离子电池Li2NixMn1-xSiO4(x=0.4～0.7)正极材料的电化学性能

摘要

采用湿化学方法,结合高温固相反应法制备了锂离子电池正极材料Li2NixMn1-xSiO4(x=0.4,0.5,0.6,0.7),以蔗糖为碳源对Li2NixMn1-xSiO4材料进行表面包覆.运用XRD、SEM、循环伏安测试和充放电循环等方法表征了Li2NixMn1-xSiO4的结构与电化学性能.XRD结果表明,Li2NixMn1-xSiO4/C固溶体属于Pmn21空间群结构.制备的Li2Nio.4Mn0.6SiO4/C具有较好的电化学性能,首次循环的充放电容量分别为219.9,132.4 mAh/g,循环20次后的可逆容量为72 mAh/g.%A cathode material Li2 NixMn1-xSiO4(x =0.4, 0.5, 0.6, 0.7) was synthesized by wet chemical process in combination with high-temperature solid-state reaction method and was coated with carbon by using sucrose as carbon source. The structural and electrochemical performances of Li2NixMn1-xSiO4 were characterized by X-ray diffraction, scanning electron microscopy (SEM), cyclic voltammetry and charge-discharge test methods. XRD results showed that the solid solution of Li2NixMn1-xSiO4 had a structure of Pmn21 space group. The prepared Li2Ni0.4Mn0.6SiO4/C cathode showed good electrochemical performance. Its charge capacity and discharge capacity were 219. 9 mAh/g and 132. 4 mAh/g in the first cycle, respectively. The reversible capacity was stabilized at about 72 mAh/g after 20 cycles.