碳包覆磷酸铁锂/石墨烯正极材料的制备及电化学性能

Preparation and electrochemical properties of carboncoated lithium iron phosphate/graphene anode materials

为提高锂离子电池正极材料的放电比容量,采用固相合成法制备了不同石墨烯质量分数的碳包覆磷酸铁锂/石墨烯正极材料,通过XRD、SEM、TEM分析复合材料的微观结构及形貌特征,采用电池测试系统和电化学工作站对锂离子电池正极材料进行电化学性能测试。结果表明:制备的复合正极材料晶型结构完整,体现出了磷酸铁锂典型的橄榄石结构;当石墨烯质量分数为10%时,在0.1C下,锂离子电池的充放电性能达到最好,首次充电比容量可达169.07 mAh/g,放电比容量为144.12 mAh/g。该复合材料的倍率性能良好,有效减小了电池极化和电池内阻,提高了锂离子电池性能。

This paper describes a study designed to improve the specific discharge capacity of positive materials for lithium ion batteries.The study involves preparing the carbon coated lithium iron phosphate/graphene cathode materials with different graphene contents by solid-phase synthesis;analyzing the microstructure and morphology of the composite by X-ray diffractometer,scanning electron microscope and transmission electron microscope;and testing the electrochemical properties of lithium ion battery anode materials by battery test system and electrochemical workstation.The results show that the composite anode material is of complete crystal structure,typical of olivine structure of lithium iron phosphate;in the presence of the content of graphene of 10%,lithium-ion batteries exhibit the best charge-discharge performance at 0.1 C,the first charge specific capacity up to 169.07 mAh/g and discharge specific capacity of 144.12 mAh/g.The composite features a better rate performance,enabling an effective reduction in the polarization and internal resistance of the battery and thus an improvement in the performance of the lithium-ion battery.