Preparation and electrochemical properties of LiFePO4 cathode materials doped with metal ions
Ag doped LiFePO4 cathode material was prepared by sol-gel method with Ag as the doping element,and CR2032 button cell was assembled based on it.The influence of metal Ag doping molar ratio on the phase structure,microstructure,and corresponding electrochemical performance of LiFePO4 batteries was studied.The results showed that Ag doped LiFePO4 had an olivine like structure with rod-shaped small particles,with a length of approximately 350-500 nm and a width of approximately 100 nm.There was slight agglomeration be-tween the particles.The charge and discharge efficiency of LiFePO4 cathode materials doped with different mo-lar ratios of Ag exceeds 95％.The appropriate doping of Ag molar ratios improved the cycling stability,initial discharge specific capacity,and capacity retention of LiFePO4.As the molar ratio of Ag doping increased,the maximum discharge specific capacity of LiFePO4 first increased and then decreased.The discharge specific ca-pacity of LiFePO4 with a 3％Ag molar ratio reached its maximum value of 123.4 mAh/g.After 30 cycles,the maximum discharge specific capacity was 70.4 mAh/g,and the capacity retention rate was 57.05％.The corre-sponding charge transfer resistance was 632.7 Ω.It can be seen that the comprehensive performance of 3％Ag LiFePO4 is the best.
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