Al和Mg共掺杂LiFePO_4/C正极材料的电化学性能研究  

Electrochemical Performances of LiFePO_4/C via Al and Mg Co-doping

作　　者：肖资龙 张经济 张志杰 王红强 李庆余 刘国壮 XIAO Zi-Long;ZHANG Jing-ji;ZHANG Zhi-jie;WANG Hong-qiang;LI Qing-yu;LIU Guo-zhuang(Guangxi Key Laboratory of Low Carbon Energy Materials,School of Chemistry and Pharmaceutical Sciences,Guangxi Normal University,Guilin 541004,Guangxi,China;Xiamen Rizhen Power Technology Co Ltd,Xiamen 361000,Fujian,China;Guangxi Zhuoneng New Energy Technology Co Ltd,Qinzhou 535000,Guangxi,China)

机构地区：[1]广西师范大学化学与药学学院广西低碳能源材料重点实验室,广西桂林541004 [2]厦门日臻动力电源科技有限公司,福建厦门361000 [3]广西卓能新能源科技有限公司,广西钦州535000

出　　处：《矿冶工程》2018年第5期148-151,156,共5页Mining and Metallurgical Engineering

基　　金：广西科学研究与技术开发计划(桂科AA16380042;桂科攻1598008-14);桂林科学研究与技术开发计划(20150106-3;2016010502-2);国家自然科学基金(51762006)

摘　　要：采用高温固相法合成了LiFePO_4/C和Al、Mg共掺杂的LiFe_(0.95)Al_(0.03)Mg_(0.02)PO_4/C复合材料。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、能量仪(EDS)、恒流充放电测试、循环伏安法(CV)等手段对材料的结构、形貌及电化学性能进行了表征。XRD结果表明,Al、Mg共掺杂后的样品并没有破坏LiFePO_4的橄榄石结构,同时还增强了LiFePO_4结构的稳定性、提高了电子导电性和Li+扩散速度;通过SEM和EDS观测到LiFePO_4呈球形颗粒,并在复合样品中检测到有Al和Mg元素存在。分别以0.5C、1C、3C和5C倍率充放电,LiFe_(0.95)Al_(0.03)Mg_(0.02)PO_4/C的放电比容量分别为145.1、142.6、133.2和124.9 m Ah/g; 1C倍率下循环30次后仍保持99.2%的初始容量,显示出良好的循环寿命。The LiFePO4/C and Al-Mg co-doped LiFe0.95Al0.03Mg0.02PO4/C composites were synthesized by a simple hightemperature solid-state method. The structure, morphology and electrochemical performances of the samples were characterized by means of X-ray diffraction （XRD）, scanning electron microscope （SEM）, energy dispersive spectrometer（EDS）, charge/discharge tests and cyclic vohammograms （CV）. XRD resuhs of the Al-Mg co-doped samples showed that the olivine structure of LiFePO4 hadn＇t been destroyed, but also the framework of LiFePO4 had been stabilized, with both electrical conductivity and Li-ion diffusion velocity enhanced. SEM and EDS observations showed that LiFePO4 is a spherical particle, and also elements of Al and Mg were detected to he existed in the composite samples. The specific capacity of LiFe0.95A10.03Mg0.02PO4/C was 145.1, 142.6, 133.2 and 124.9 mAh/g, respectively, at the discharge rate of 0.5C, 1C ,3C,5C. It remained 99.2% of its initial capacity alter 30 cycles at discharge rate of 1C, showing an outstanding cycling life.

关 键 词：锂离子电池 正极材料 磷酸铁锂 LIFEPO4/C 共掺杂 铝 镁 高温固相法 电化学性能 

分 类 号：TM911[电气工程—电力电子与电力传动]