石墨烯掺杂LiFePO4电极材料的合成及其电化学性能

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2 mol·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、64 mAh·g-1,而石墨烯改性的LiFePO4微球的比容量分别为141、105 mAh·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.

Synthesis and Electrochemical Performance of Graphene Modified LiFePO4 Cathode Materials

Graphene-modified mesoporous LiFePO4 microsphere composites were synthesized by a hydrothermal method and subsequent annealing.X-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM),Fourier transform infrared (FT-IR) spectroscopy,and galvanostatic charge-discharge techniques were used to characterize the morphology,structure and electrochemical performance of the resulting composites.The graphene-modified LiFePO4 microspheres exhibited a high discharge capacity of 141 mAh·g-1 at 1C,and 105 mAh·g-1 at 50C,while LiFePO4/C only delivered 137 mAh·g-1 at 1C,64 mAh·g-1 at 50C in an aqueous electrolyte of 2 mol·L-1 LiNO3.The graphene-modified LiFePO4 exhibited excellent cyclability compared with LiFePO4/C,with a capacity retention of about 83.7% after 60 cycles versus about 70.2% for LiFePO4/C.The improved electrochemical performance is attributed to the formation of a three-dimensional (3D) graphene network.