Ni,Cr掺杂对LiFePO_4/C电化学性能的影响  

Effect of Ni,Cr doping on the electrochemical performances of LiFePO_4/C

作　　者：肖志平[1] 王英[1] 唐仁衡[1] 肖方明[1] 

机构地区：[1]广东省工业技术研究院(广州有色金属研究院),广东广州510650

出　　处：《材料研究与应用》2014年第4期232-236,共5页Materials Research and Application

摘　　要：采用二步固相反应在惰性气氛下合成了橄榄石型LiFe0.98M0.02PO4/C（M=Ni,Cr）复合正极材料.通过XRD,SEM及电化学测试等手段对材料的性能进行分析.研究结果表明：少量Ni^2＋,Cr^3＋的掺杂虽然未改变LiFePO4晶体结构,但改善了材料的颗粒形貌,降低了粒径（粒径约200nm）,增强了LiFe0.98M0.02PO4/C材料的导电能力,比未掺杂的LiFePO4/C具有更好的电化学性能.在2.5-4.2V下充放电,LiFe0.98Cr0.02PO4/C材料0.2C的首次放电比容量为146.7mA·h·g^-1,循环50次的容量保持率为98.1%,10C放电比容量达116.3mA·h·g^-1.In this study,olivine LiFe0.98M0.02PO4/C（M=Ni,Cr）composite cathode materials were synthesized by the two-step solid state reaction method in an inert atmosphere.The performances of the obtained materials were analyzed by XRD,SEM and electrochemical tests.The results indicated that the structure of lithium iron phosphate was not changed,while both its particle morphology（the particle size was reduced to 200nm）and conductivity of LiFe0.98M0.02PO4/C materials were improved by doping of small amounts of Ni^2＋,Cr^3＋.The better electrochemical performance for the doped materials was obtained than that of the pristine LiFePO4/C.When the material LiFe0.98Cr0.02PO4/C was charged-discharged at 2.5-4.2V,the discharge capacity of 146.7mA·h·g^-1 was exhibited initially and retained 98.1%after 50 cycles at 0.2C,and the 10.0Cdischarge capacity was achieved to 116.3mA·h·g^-1.

关 键 词：磷酸铁锂 掺杂 锂离子电池 电化学性能 

分 类 号：TM912.9[电气工程—电力电子与电力传动]