LiFePO_4/膨胀石墨复合材料的制备及性能

Synthesis and characterization of lithium iron phosphate/exfoliated graphite composite material

采用机械球磨法合成LiFePO_4/膨胀石墨复合材料,讨论了膨胀石墨不同添加量对复合材料电化学性能的影响。运用扫描电镜、四探针测试和恒流充放电等对材料的表面形貌、电阻率和电化学性能进行了研究。结果表明:当膨胀石墨的添加量为质量分数1.0%时,其电化学性能最优异,0.2C放电比容量可达到164.2mAh/g,1.0C循环60次后,其放电比容量仍有151.6mAh/g,3.0C充放电后,其容量保持率仍有89.6%。

LiFePO4/exfoliated graphite（EG） composite materials were synthesized by mechanical ball-milling. Effect of different exfoliated graphite doping amounts on the electrochemical performance of LiFePO4/EG samples was discussed. The grain morphology, resistivity and electrochemical performance of the materials were characterized by scanning electron microscope （SEM）, 4-point probes resistivity measurement and galvanostatic charge/discharge（DC） methods. The results show that when the exfoliated graphite mass fraction is 1.0%, it exhibites a superior electrochemical performance. The discharge specific capacity is 164.2 mAh/g at rate of 0.2C, and it still retains at a high level with a discharge specific capacity of 151.6 mAh/g after 60 cycles at rate of 1.0C, and a capacity retention of 89.6% after charge/discharge at rate of 3.0C.