烧结温度对LiMn_2O_4基502030锂离子电池电化学性能的影响  

Effect of heat annealing temperature on the electrochemical performances of LiMn_2O_4 cathode material for lithium-ion batteries

作　　者：李庆余[1] 廖涛 赖飞燕 莫仁山 吴强[1] 史洪峰 LI Qingyu;LIAO Tao;LAI Feiyan;MO Renshan;WU Qiang;SHI Hongfeng(Guangxi Key Laboratory of Low Carbon Energy Materials,Guangxi Normal University,Guilin 541004,China;Anhui EIKTO Battery Co.,Ltd.,Xuancheng 242000,China)

机构地区：[1]广西师范大学广西低碳能源材料重点实验室,广西桂林541004 [2]安徽益佳通电池有限公司,安徽宣城242000

出　　处：《功能材料》2018年第4期4184-4188,共5页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(51762006);广西科学研究与技术开发计划资助项目(桂科AA16380042;桂科攻1598008-14);桂林市第一批科学研究与技术开发资助项目(2016010502-2)

摘　　要：为了研究不同烧结温度对La_(0.7)Sr_(0.3)MnO_3@LiMn_2O_4(LLMO)材料电化学性能的影响,采用X射线衍射(XRD)和透射电子显微镜(TEM)对其结构和形貌进行表征,将LLMO材料制作成502030型软包锂离子电池,测试其电化学性能。XRD结果表明,La_(0.7)Sr_(0.3)MnO_3包覆后的材料没有其它衍射峰,说明质量分数为1.0%的La_(0.7)Sr_(0.3)MnO_3包覆并没有改变LiMn_2O_4结构;TEM表明烧结温度为500℃时,表面包覆分布均匀,涂层厚度约为80nm。对材料进行电化学性能测试,测试结果表明,纯相LiMn_2O_4首次充放电(0.1C倍率)效率为85.97%,循环400周后容量保持率为82.09%;500℃热处理的样品首次充放电效率为98.74%,循环400周后容量保持率为88.89%。实验结果表明,经过包覆后LiMn_2O_4材料的电化学性能得到了明显的提高。In order to study the electrochemical performance of La0.7Sr0.3MnO3@LiMn2O4(LLMO)cathode material at different heat annealing temperatures,the structure and morphology of La0.7Sr0.3MnO3 coating on the surface of spinel LiMn 2O 4 cathode materials were investigated by X-ray diffraction(XRD)and transmission electron microscopy(TEM).And the electrochemical performances of the LLMO samples were tested by electrochemical tests via full cells(502030).The XRD results show that there is no other diffraction peak in the La0.7Sr0.3MnO3 coating with a mass fraction of 1.0%,indicating that the La0.7Sr0.3MnO3 coating does not change the spinel structure of LiMn 2O 4 cathode material,because the atoms of coating material can only adhere to the surface rather than enter the spinel lattice.Heat annealing temperature has a significant effect on the electrochemical performance of the La0.7Sr0.3MnO3 coating.At the mid-temperature(500℃),TEM results exhibit a more uniform and continuous coating,and its thickness is about 80 nm.The electrochemical results indicate that LLMO sample exhibits a good initial charge-discharge efficiency and cycle stability.The initial charge-discharge(0.1 C rate)efficiency of pure LiMn 2O 4 is 85.97%,and the capacity retention rate is 82.09%after 400 cycles,while the initial charge-discharge efficiency of the sample annealed at 500℃is 98.74%,and the capacity retention rate is 88.89%after 400 cycles.Thus,the La 0.7 Sr 0.3 MnO 3@LiMn 2O 4 annealed at 500℃has an excellent electrochemical performance,showing potential for high power applications in lithium ion batteries.

关 键 词：锂离子电池 La0.7Sr0.3MnO3涂层 LIMN2O4 烧结温度 

分 类 号：TM912.9[电气工程—电力电子与电力传动]