石墨烯掺杂LiFePO_电极材料的合成及其电化学性能_徐科.doc

------------------------------------------------------------------------------------------------ —————————————————————————————————————— 石墨烯掺杂LiFePO_4电极材料的合成及其电化学性能_徐科 January [Article]物理化学学报(WuliHuaxueXuebao)ActaPhys.-Chim.Sin.2012,28(1),105-110doi:10.3866/PKU.WHXB201228105105 石墨烯掺杂LiFePO4电极材料的合成及其电化学性能 徐科申来法米常焕张校刚* (南京航空航天大学材料科学与技术学院,南京210016) 摘要:采用水热辅助法合成石墨烯改性的LiFePO4多孔微球电极材料.并对材料进行了X射线衍射(XRD),扫 描电子显微镜(SEM),透射电子显微镜(TEM),傅里叶变换红外(FT-IR)光谱,充放电等表征.从结果可以看出在 2mol·L-1LiNO3电解液体系中单纯包碳的LiFePO4微球在1C、50C倍率时的比容量分别为137、64mAh·g-1, 而石墨烯改性的LiFePO4微球的比容量分别为141、105mAh·g-1,表现出较好的倍率特性.恒流循环充放电测 试60次后两种材料容量保持率分别为70.2%、83.7%.说明掺杂石墨烯构成的三维导电网络能明显改善 LiFePO4的电化学性能. 关键词:LiFePO4;石墨烯;水热法;锂离子电池 O646中图分类号: SynthesisandElectrochemicalPerformanceofGrapheneModified LiFePO4CathodeMaterials XUKeSHENLai-FaMIChang-HuanZHANGXiao-Gang* (CollegeofMaterialScienceandEngineering,NanjingUniversityofAeronauticsandAstronautics,Nanjing210016,P.R.China) Abstract:Graphene-modifiedmesoporousLiFePO4microspherecompositesweresynthesizedbya hydrothermalmethodandsubsequentannealing.X-raydiffraction(XRD),scanningelectronmicroscopy (SEM),transmissionelectronmicroscopy(TEM),Fouriertransforminfrared(FT-IR)spectroscopy,and galvanostaticcharge-dischargetechniqueswereusedtocharacterizethemorphology,structureand electrochemicalperformanceoftheresultingcomposites.Thegraphene-modifiedLiFePO4microspheres exhibitedahighdischargecapacityof141mAh·g-1at1C,and105mAh·g-1at50C,whileLiFePO4/Conly delivered137mAh·g-1at1C,64mAh·g-1at50Cinanaqueouselectrolyteof2mol·L-1LiNO3.The graphene-modifiedLiFePO4exhibitedexcellentcyclabilitycomparedwithLiFePO4/C,withacapacity retentionofabout83.7%after60cyclesversusabout70.2%forLiFePO4/C.Theimprovedelectrochemical performanceisattributedtotheformationofathree-dimensional(3D)graphenenetwork. KeyWords:Lithiumironphosphate;Graphene;Hydrothermal;Li-ionbattery 1引言 能源是人类社会发展与稳定的重要支柱,现在