Mn2+、Ti4+掺杂对Li2FeSiO4/C正极材料电化学性能的影响  

Influence of Mn2+ and Ti4+ doping on the electrochemical property of Li2FeSiO4/C

作　　者：刘平 龚勇 李琳 代祖洋 辜其隆 程伟 陈建 Liu Ping;Gong Yong;Li Lin;Dai Zuyang;Gu Qilong;Cheng Wei;Chen Jian(School of Materials Science and Engineering,Sichuan University of Science Engineering,Sichuan Province Key Laboratory for Corrosion and Protection of Material, Sichuan Universityof Science & Engineering,Zigong 643000)

机构地区：[1]四川理工学院材料科学与工程学院材料腐蚀与防护四川省重点实验室

出　　处：《化工新型材料》2019年第6期126-130,135,共6页New Chemical Materials

基　　金：国家自然科学基金面上项目(51572177);四川省科技厅项目(2017JY0158);四川省科技计划项目(2017GZ0121);材料腐蚀与防护四川省重点实验室开放基金(2017CL12);四川理工学院大学生创新创业训练计划项目(CX2017004)

摘　　要：针对锂离子电池正极材料Li2FeSiO4导电率和锂离子扩散率低的缺点,采用溶胶凝胶-微波法合成纳米复合材料硅酸亚铁锂(Li2FeSiO4/C)正极材料。借助X射线衍射、扫描电镜和电化学方法,表征了Mn2+、Ti4+掺杂对Li2FeSiO4结构、微观形貌及电化学性能的影响。结果表明:当Mn2+取代量x=0~0.15时,充放电比容量逐渐增加,x=0.15时,充放比电容量高达172.9mA·h/g(y=0.05,152.1mAh/g);但当Mn2+取代量x=0.20时,充(放)电容量降至118.5mA·h/g(110.9mA·h/g)。Ti4+掺杂优选条件为Li2Fe0.85Mn0.15SiO4测试后发现最终合成较优的LiFe0.80Mn0.15Ti0.05SiO4(y=0.05)首次充(放)电比容量高达178.2mA·h/g(166.7mA·h/g),并且在0.1C倍率下循环20次后容量保持率可达96.4%。The sol-gel method was used to synthesize lithium iron silicate(Li2 FeSiO4/C)cathode nanocomposite in order to overcome the shortcomings of Li2 FeSiO4 low conductivity and low lithium ion diffusion rate in the lithium ion battery.The structural,morphological and electrochemical properties of Li2 FeSiO4/C were characterized by XRD,SEM and electrochemical methods.The results showed that the charge/discharge capacitance increased gradually as increasing the Mn2+substitution concentration x,and the maximum of charge/discharge capacitance was 172.9 mAh/g(152.1 mAh/g)at x=0.15.When the Mn2+substitution amount x=0.20,the charge/discharge capacitance drop to 118.5 mAh/g(110.9 mAh/g).For Ti2+doping,the best condition was Li2 Fe0.85 Mn0.15 SiO4.It was found that LiFe0.80 Mn0.15 Ti0.05 TiO4(y =0.05)had the maximum charge/discharge capacitance of178.2 mAh/g(166.7 mAh/g),and the capacitance retention rate was 96.4% after 20 cycles of 0.1 Cmagnification.

关 键 词：正极材料 离子掺杂 溶胶凝胶-微波法 电化学性能 

分 类 号：TM912[电气工程—电力电子与电力传动]