过渡金属离子掺杂对磷酸铁锂性能的影响  

Effect of Transition Metal Ions Doping on the Performance of LiFePO_4/C Cathode Material

作　　者：叶长福 郑会元[1] 劳铭 周文政[1] 郭进[1] 黎光旭[1] 

机构地区：[1]广西大学物理科学与工程技术学院,广西高校新能源材料及相关技术重点实验室,南宁530004

出　　处：《材料导报》2017年第2期29-32,共4页Materials Reports

基　　金：国家自然科学基金(61264006);广西自然科学基金(2014GXNSFAA118340);广西自然科学基金杰出青年基金(2013GXNSFGA019007)

摘　　要：以碳酸锂、草酸亚铁、磷酸二氢铵、葡萄糖为原料,添加不同的过渡金属乙酸盐(乙酸锰、乙酸钴、乙酸镍、乙酸锌),在氩气保护下采用高温固相法制备LiFePO_4/C复合材料。采用X射线衍射、扫描电子显微镜、同步热分析、恒电流充放电、电化学阻抗、循环伏安等方法研究掺杂金属离子及掺杂量对LiFePO_4/C晶体结构和电化学性能的影响。结果表明,LiFe_(0.9)M_(0.1)PO_4/C(M=Mn、Co、Ni、Zn)样品的晶体结构均与橄榄石型LiFePO_4相同。掺杂过渡金属阳离子可以提高LiFePO_4/C的还原电位,降低氧化电位,缩小氧化还原峰间距,提高化学反应的可逆性。掺杂后的样品在5C下的放电性能较好,以LiFe0.9Ni0.1PO4/C的放电容量最高,达到89mAh/g。By adding different transition metal acetates（manganese acetate, cobaltous acetate, nickel acetate, zinc acetate）, LiFePO4/C composite materials were synthesized for lithium rechargeable batteries by high temperature solid-state reaction under the protection of argon, using Li2CO3, FeC2O4·2H2O, NH4H2PO4, C6H12O6 （glucose） as raw materials. Effect of doping transition metal ions on crystal structure and performance of the sample was investigated by using X-ray diffraction, scanning electron microsco- py, thermogravimetric analysis, galvanostatic charge discharge and electrochemical impedance spectroscopy, cyclic voltammetry. The results indicated that LiFe0. 9 M0.1 PO4/C （M= Mn, Co, Ni, Zn） and LiFePO4 have the same crystal structure of olivine-style. Doping transition metal ions can increase the reduction potential of LiFePO4/C, decrease the oxidation potential, reduce the distance between redox peaks, and improve the reversibility of the chemical reaction. The doped samples have a better discharge performance at 5C, especially LiFeo. 9 Ni0.1PO4/C which has the highest discharge specific capacity reaching 89 mAh/g.

关 键 词：LIFEPO4/C 复合材料 过渡金属 掺杂 

分 类 号：TM912.9[电气工程—电力电子与电力传动]