混合铁源制备碳包覆磷酸铁锂

摘要

Carbon coated lithium ferrous phosphate(LiFePO4/C)as cathode material of Li-ion battery was synthesized by solid state reaction method using mix iron sources. The surface morphology,crystal structure and the electrochemical performance were charac-terized by SEM,XRD,charge-discharge testing and electrochemical impedance spectra(EIS). The composite synthesized at 700 ℃with mixed iron sources n(FeC2 O4·2H2 O)∶n(FePO4 )=1∶1 had better electrochemical performance,when charged-discharged in 2.5 ~4.1 V,the 0.2 C specific discharge capacity was 165.9 mAh/g,the specific discharge capacity in the initial and 20th cycle at 2.0 C was 135.3 mAh/g and 141.9 mAh/g,respectively.%以FeC2 O4·2H2 O和FePO4作为混合铁源，采用高温固相法制备锂离子电池正极材料碳包覆磷酸铁锂（LiFePO4/C）。采用SEM、XRD、恒电流充放电测试和交流阻抗谱对材料的表面形貌、物相结构和电化学性能进行了分析。在700℃、混合铁源n（FeC2 O4·2H2 O）∶n（FePO4）＝1∶1时制备的LiFePO4/C的电化学性能较好。在2.5～4.1 V充放电，0.2 C时的放电比容量为165.9 mAh/g，2.0 C首次和第20次循环的放电比容量分别为135.3 mAh/g、141.9 mAh/g。