掺铌硅酸亚铁锂正极材料的电化学性能  

Electrochemical performance of the Nb doped Li_2FeSiO_4 positive materials

作　　者：伍仁强[1] 陈梅蓉[1] 韩铭[1] 黄娟[1] 童庆松[1] 

机构地区：[1]福建师范大学化学与材料学院,福建福州350007

出　　处：《吉林化工学院学报》2012年第3期1-5,共5页Journal of Jilin Institute of Chemical Technology

基　　金：福建省科技厅重点资助项目(2010I0005);国家自然科学基金资助项目(20973038)

摘　　要：采用固相烧结法,以LiOH、FeC2O4.2H2O、Nb2O5、正硅酸四乙酯和蔗糖为原料制备出单斜结构的Li2.05FexNb2(1-x)/3SiO4/C(x=1,0.99,0.98,0.96,0.94,0.92,0.90)系列样品.通过红外光谱、X射线衍射、扫描电镜、恒电流充放电测试、交流阻抗和循环伏安法等方法研究了制备样品的结构及电化学性能.实验结果表明,颗粒尺寸介于0.2～1.5μm之间的Li2.05Fe0.96Nb0.026 7SiO4/C的充放电性能最好,在0.3C倍率电流下,第1次循环的放电容量为116.6 mAh/g,第30循环的放电容量为78.3 mAh/g.掺铌减少了样品的电荷传递阻抗,提高了锂离子的扩散系数.Li2.05FexNb2（1-x）/3SiO4/C（x=1,0.99,0.98,0.96,0.94,0.92,0.90）were prepared by the solid reaction of LiOHoH2O,FeC2O4o2H2O,C8H20OSi,Nb2O5 and sugar.The prepared samples were characterized by the FTIR,XRD,SEM,charge-discharge cycle,electrochemical impedance and cyclic voltammogram.The experimental results show that Li2.05Fe0.96Nb0.0267SiO4/C with the particle-size of 0.2-1.5 μm exhibits the best charge-discharge performance in the as-prepared samples,which exhibits a capacity 116.6 mAh/g in the 1st cycle and 78.3 mAh/g in the 30th cycle.The niobium doping reduces charge transfer impedance,and increases the lithium-ion diffusion coefficient than that of undoped sample.

关 键 词：正极材料 硅酸亚铁锂 Nb掺杂剂 可充性 

分 类 号：O614.111.1[理学—无机化学] O614.711[理学—化学]