三相碳改性磷酸铁锂复合材料的制备及其电化学性能研究

Preparation and Electrochemical Performance of Three-Phase Carbon Modified Lithium Iron Phosphate Composite

以磷酸铁、碳酸锂为原材料,葡萄糖、碳纳米管和石墨烯为导电剂,通过砂磨工艺及碳热还原法制备了高性能磷酸铁锂、无定型碳、石墨烯、碳纳米管复合正极材料LFP/C/G/CNTs。材料表征结果表明,碳纳米管、石墨烯和无定形碳与磷酸铁锂复合在一起,成功构建了高速电子传输网络;电化学性能测试表明,LFP/C/G/CNTs具有良好的循环性能和倍率性能。在0.1C电流密度下,LFP/C/G/CNTs放电比容量为161.5 mAh/g;在5C电流密度下,LFP/C/G/CNTs复合材料放电比容量仍达126.5 mAh/g;在2C电流密度下,循环200次后,LFP/C/G/CNTs放电比容量152.1 mAh/g,容量保持率为99.6%。

The LFP/C/G/CNTs,a high-performance composite cathode material of lithium iron phosphate(LFP),amorphous carbon,graphene and carbon nanotube,was prepared by using the sand milling process and carbon thermal reduction method,with iron phosphate and lithium carbonate as raw materials,and glucose,carbon nanotubes(CNTs)and graphene as conductive agents.The characterization results indicate that CNTs,graphene,and amorphous carbon are well combined with LFP,thereby successfully constructing a high-speed electron transmission network.The electrochemical performance test shows that the LFP/C/G/CNTs can exhibit good cycling performance and rate performance.It can deliver a specific discharge capacity of 161.5 mAh/g at a current density of 0.1C,and 126.5 mAh/g at 5C.After 200 cycles at the current density of 2C,it can still deliver a specific discharge capacity of 152.1 mAh/g,with the capacity retention rate of 99.6%.