Li_(2)MnSiO_(4)/C锂电池复合电极材料制备及电化学性能研究  

Production of Li_(2)MnSiO_(4)/C Composites as Electrodes for Lithium Ion Battery and Its Electrochemical Properties

作　　者：华丽[1,2] 曾建华[1] 胡庆兰[1] 欧小文 朱玉涵 刘俊逸 邵玉娇[1] 汪云凡 HUA Li;ZENG Jian-hua;HU Qing-lan;OU Xiao-wen;ZHU Yu-han;LIU Jun-yi;SHAO Yu-jiao;WANG Yun-fan(School of Chemistry and Life Science, Hubei University of Education, Wuhan 430205, China;School of Material Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China)

机构地区：[1]湖北第二师范学院化学与生命科学学院,武汉430205 [2]华中科技大学材料科学与工程学院,武汉430074

出　　处：《湖北第二师范学院学报》2021年第8期1-6,共6页Journal of Hubei University of Education

基　　金：湖北第二师范学院校级教学研究项目“‘互联网+’视域下我校创新创业教育与校企合作实践实训深度融合探究”(X2019013);湖北第二师范学院科学研究“新型冠状病毒防治”专项项目研究(20XGZX10)。

摘　　要：采用溶胶-凝胶法合成Li_(2)MnSiO_(4)/C锂电池复合正极材料,并用XRD和ESEM分别进行晶体结构和形貌表征,并进行电化学性能测试。结果显示,复合材料呈类球状颗粒,粒间无团簇,分散性较好,晶体属于正交晶系Pmn21空间群。充放电测试结果表明,首次充放电比容量分别为153.6mAh/g和144mAh/g,50次循环后充放电比容量分别为140mAh/g和134mAh/g,100次循环后充放电比容量分别为131mAh/g和125mAh/g;经过200次充放电循环后比容量依然保持在61mAh/g和60mAh/g。在不同倍率下循环稳定性测试结果表明,高倍率下电流密度越大充放电越不稳定。交流阻抗测试结果显示:对比Li_(2)MnSiO_(4),Li_(2)MnSiO_(4)/C电极材料的接触电阻R1、电极表面电荷转移电阻R2扩散阻抗Ws均要小,表明碳复合有利于提高Li_(2)MnSiO_(4)电极材料的电化学性能。The material for the positive pole of Li_(2)MnSiO_(4)/C lithium battery is synthesized with sol-gel method.The crystal structure and surface are described with XRD and ESEM.Electrochemical performance test shows that Li_(2)MnSiO_(4) nanoparticles are spherical.There is no clusters among the well dispersed particles.Li_(2)MnSiO_(4)/C crystals belong to the orthogonal crystal system with Pmn21 spatial group.Tests of charge and discharge show that first charge and discharge capacities are 153.6mAh/g and 144mAh/g,respectively.Charge and discharge capacities are 140 and 134 mAh/g after 50 cycles,131mAh/g and 125 mAh/g after 100 cycles and 61mAh/g and 60 mAh/g after 200 cycles.Cyclic stability tests at different rates show that the higher the current density is,the more unstable the charge and discharge will be.AC impedance tests show that the contact resistance R1,the charge transfer resistance R2 and the diffusion impedance Ws of the Li_(2)MnSiO_(4)/C electrode material are all lower than that of the Li_(2)MnSiO_(4) electrode material,indicating that carbon composite helps improve the electrochemical performance of the Li_(2)MnSiO_(4) electrode material.

关 键 词：锂离子电池 复合正极材料 Li_(2)MnSiO_(4)/C 电化学性能 

分 类 号：O646[理学—物理化学] TM912.2[理学—化学]