Cr^(3+)对LiFePO_4/C材料结构和电化学性能的影响  

Effects of Cr Doping on Structure and Electrochemical Performance of LiFePO_4/C

作　　者：章兴石[1,2] 唐仁衡[1] 肖方明[1] 王英[1] 肖志平[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)稀有金属研究所,广州510650 [2]华南理工大学材料科学与工程学院,广州510640

出　　处：《材料导报》2014年第16期44-46,共3页Materials Reports

基　　金：珠海市战略性新兴产业重大项目;珠海市产学研合作专项资金(2011A05010003)

摘　　要：采用二步固相反应法合成了具有橄榄石结构的LiFe0.98Cr0.02PO4/C复合正极材料,并通过XRD、SEM、恒流充放电、循环伏安等分析测试手段对材料的物相结构及电化学性能进行表征。结果表明:LiFePO4材料引入Cr3+未改变其原有的晶体结构,但合成材料的颗粒尺寸明显减小,颗粒粒径约为200nm;获得的LiFe0.98Cr0.02-PO4/C复合材料具有良好的电化学性能,0.2C倍率下首次放电比容量为144.9mAh·g-1,50次循环后,容量保持率为99.6%,10C倍率放电比容量可达到116.3mAh·g-1。循环伏安性能测试表明Cr3+的掺杂提高了Li+在材料中脱嵌过程的可逆性。LiFe0.98 Cr0.02 PO4/C composite was synthesized by two-step solid state reaction. And the phase structure and electrochemical properties of the composite material were characterized through XRD, SEM and constant current charge and discharge, cyclic voltammetric analysis test. The experiment results show that Cr doping does not destroy the lattice structure of LiFePO4, hut the particle size has been deeply reduced, with approximately 200 nm. LiFe0. 98 Cr0.02 PO4/C composite delivers 144.9 mAh·g-1 , at the 0.2C rate for the first cycles. After 50 cycles, its capacity remained 99.6% of initial capacity. At the high rates of 10C, this material exhibits high capacities of 116. 3 mAh·g-1. The CV results revealed that Cr could improve the reversibility of LiFePO4/C composite.

关 键 词：磷酸铁锂 CR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]