摘要
LiFe1–xCexPO4/C cathode materials were synthesized by solid-state reaction method. The effects of various Ce-doping amounts on the microstructure and electrochemical performance of LiFePO4/C cathode material were intensively investigated. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), galvanostatic charge-discharge meas-urements and electrochemical impedance spectroscopy (EIS). The results indicated that Ce-doping did not destroy the lattice structure of LiFePO4/C, while enlarged the lattice volume tailored the particle size, decreased charge transfer resistance, increased electrical conductivity and Li-ion diffusion rate of LiFePO4/C, and thus markedly enhanced the electrochemical performance of the LiFePO4/C. Electrochemical test results showed that the LiFe0.9Ce0.1PO4/C sample exhibited the best electrochemical performance with initial spe-cific capacity of 155.4 mAh/g at 0.2 C , the capacity retention ratios of 99.6% at 100 cycles at 1 C and delivered a discharge capacity of 160.1 (0.1 C), 156.6 (0.2 C), 151.2 (0.5 C), 147.6 (1 C), 140.7 (2 C) and 136.7 mAh/g (5 C), respectively, presented the best rate capacity among all the samples. EIS results demonstrated that the transfer resistance of the sample decreased greatly by doping an ap-propriate amount of Ce.
LiFe1–xCexPO4/C cathode materials were synthesized by solid-state reaction method. The effects of various Ce-doping amounts on the microstructure and electrochemical performance of LiFePO4/C cathode material were intensively investigated. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), galvanostatic charge-discharge meas-urements and electrochemical impedance spectroscopy (EIS). The results indicated that Ce-doping did not destroy the lattice structure of LiFePO4/C, while enlarged the lattice volume tailored the particle size, decreased charge transfer resistance, increased electrical conductivity and Li-ion diffusion rate of LiFePO4/C, and thus markedly enhanced the electrochemical performance of the LiFePO4/C. Electrochemical test results showed that the LiFe0.9Ce0.1PO4/C sample exhibited the best electrochemical performance with initial spe-cific capacity of 155.4 mAh/g at 0.2 C , the capacity retention ratios of 99.6% at 100 cycles at 1 C and delivered a discharge capacity of 160.1 (0.1 C), 156.6 (0.2 C), 151.2 (0.5 C), 147.6 (1 C), 140.7 (2 C) and 136.7 mAh/g (5 C), respectively, presented the best rate capacity among all the samples. EIS results demonstrated that the transfer resistance of the sample decreased greatly by doping an ap-propriate amount of Ce.
基金
supported by Hebei Province Science and Technology Program(14214902D)
