水热法制备准球形掺Ti^(4+)-LiFePO_4/C纳米粉体及温度对其电化学性能的影响  

Hydrothermal Synthesis of Quasi-spherical Nanostructured Doped Ti^(4+)-LiFePO_4/C Powder and Its Temperature-dependent Electrochemical Properties

作　　者：马丽[1] 戴亚堂[1] 欧青海[1] 王伟[1] 张欢[1] 陈玉华[1] 

机构地区：[1]西南科技大学四川省非金属复合与功能材料重点实验室一省部共建国家重点实验室培育基地,四川绵阳621010

出　　处：《精细化工》2013年第11期1208-1212,1216,共6页Fine Chemicals

摘　　要：以(NH4)2FeSO4、LiOH、Ti(SO4)2以及H3PO4为原料一步水热合成法制备不同温度下掺Ti4+-LiFePO4,然后进行碳包覆。XRD和SEM表明,制备的样品为单一相的准球形纳米粉体;激光粒度分析表明,在160℃下合成的粉体平均粒径最小,约为140 nm;恒电流充放电及电化学阻抗谱测试材料电化学性能表明,在160℃下合成的掺Ti4+-LiFePO4/C材料充放电性能最好,0.1 C倍率下首次放电容量为160.97 mA·h/g,0.5 C倍率下经过50次放电,容量保留率为95.28%,通过电化学阻抗计算出锂离子扩散系数为1.78×10-12cm2/s。Doped Ti4＋-LiFePO4/C was synthesized by one-step hydrothermal method at different temperatures using （NH4 ）2 FeSO4, LiOH, Ti （SO4 ）2 and H3 PO4 as raw materials. Then, the product was modified with carbon coating. X-ray diffraction patterns and scanning microscopy images along with energy dispersive spectroscopy mappings have verified the tom electron homogeneous existence of coated carbon and doped Ti4＋ in LiFePO4 particles with phospho-olivine structure and an average size of 140 nm at 160 ℃. The electrochemical performance of the material has been studied through galvanostatic charge-discharge measurements and electrochemical impedance spectroscopy. The material shows the best electrochemical performance at 160 ℃,with the initial discharge capacity of 160. 97 mA . h/g at 0. 1 C, a capacity retention of 95.28% after 50 cycles at 0.5 C and an increased lithium ion diffusion coefficient of 1.78 x 10-12 cmZ/s.

关 键 词：水热合成法 磷酸铁锂 纳米材料 锂离子扩散系数 功能材料 

分 类 号：TQ322.95[化学工程—合成树脂塑料工业]