锂离子电池用LiMn2O4/石墨烯复合材料的性能  

Performance of LiMn2O4/graphene composite material for Li-ion battery

作　　者：邓凌峰[1,2] 连晓辉 张淑娴 谭洁慧 DENG Ling-feng;LIAN Xiao-hui;ZHANG Shu-xian;TAN Jie-hui(School of Materials Science Engineering,Central South University of Forestry and Technology,Changsha,Hunan 410004,China;Hunan Xineng New Material Co.,Ltd.,Changsha,Hunan 410205,China)

机构地区：[1]中南林业科技大学材料科学与工程学院,湖南长沙410004 [2]湖南缚能新材料有限公司,湖南长沙410205

出　　处：《电池》2019年第2期125-128,共4页Battery Bimonthly

摘　　要：采用Hummers法制备少层氧化石墨烯(GO),再通过喷雾干燥高温固相原位还原法制备锰酸锂(LiMn2O4)/石墨烯复合正极材料。通过SEM、透射电镜(TEM)、XRD及电化学测试等方法,研究材料的结构和电化学性能。石墨烯能包覆LiMn2O4纳米颗粒团,并连接在纳米颗粒之间,减少LiMn2O4颗粒与电解液直接接触,形成纳米级的导电网络,提高LiMn2O4的循环性能和高倍率性能。在3.0-4.3V充放电,LiMn2O4/石墨烯复合材料在0.5C倍率下的放电比容量为133.0mAh/g,比LiMn2O4高11.2mAh/g;LiMn2O4/石墨缔复合材料在1.0C倍率下循环100次,放电比容量由128.7mAh/g衰减到127.8mAh/g,容量保持率为99.3%;5.0C倍率下的放电比容量达到110.9mAh/g,是0.5C时的83.3%。Micro layers of graphite oxide(GO)was prepared by Hummers method.Lithium manganese oxide(LiMn2O4)/graphene composite was prepared by spray drying high temperature solid situ reduction method.The structure and electrochemical performance of LiMn2O4/graphene composite materials were investigated systematically.Images of SEM and transmission electron microscopy(TEM)showed that graphene could effectively cover the surface of LiMn2O4 cluster nanoparticles and connect them between nanoparticles to reduce the direct contact between LiMn2O4 particles and electrolyte and to form a nanoscale conductive network,thus improved greatly cycling performance and high rate capacity of LiMn204.In particular,the discharge specific capacity of LiMn2O4/graphene composite reached 133.0mAh/g at 0.5C in 3.0-4.3V,compared with LiMn2O4,whose capacity was improved 11.2 mAh/g.After 100.0 cycles at 1.0C,the capacity of LiMn2O4/graphene composite decreased from 128.7 mAh/g to 127.8 mAh/g,which was 99.3%of the initial discharge specific capacity.When the discharge rate increased to 5.0 C,the specific discharge capacity of graphene/LiMn204 battery was 110.9 mAh/g,which was 83.3%of the one at 0.5 C.

关 键 词：石墨烯 锰酸锂(LiMn2O4) 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]