一种新碳源包覆的LiFePO4／C正极材料的合成及性能

Synthesis and Properties of LiFePO_4/C Cathode Material with a New Carbon Source

以富含植物蛋白的豆浆作为碳源,以FePO4.4H2O和LiOH.H2O为原料,采用流变相方法合成了锂离子电池正极材料LiFePO4/C.X射线衍射(XRD)和扫描电子显微镜(SEM)的表征结果显示,样品具有良好的结晶性能,平均粒径约200nm,颗粒表面有均匀网络状的碳包覆.充放电循环研究结果表明:LiFePO4/C具有稳定的电化学循环性能,LiFePO4/C正极材料在0.1C倍率下首次放电比容量达到156mAh.g-1,首次充放电效率达到98.7%;循环40次后,放电比容量为149mAh.g-1,电池容量保持率在95%以上,1C倍率下首次放电比容量达到134.7mAh.g-1,显示出较高的电化学容量和优良的循环稳定性.

We synthesized LiFePO2C composite cathode materials by the rheological phase method with vegetable protein soya bean milk as a carbon source while FePO4.4H2O and LiOH. H2O as raw materials. X-ray diffraction （XRD） and scanning electron microscopy （SEM） results showed that the LiFePO2C composite materials had good crystallinity, ultrafine sphere-like particles of 200 nm in size and in situ carbon. The electrochemical performance of LiFePO2C by galvanostatic cycling studies showed excellent cycle stability. The LiFePO4/C cathode material gave a high initial discharge capacity of 156 mAh. g-1 at 0.1C and the first columbic efficiency was 98.7%. This capacity was still 149 mAh. g-1 after 40 cycles at 0.1C and its capacity retention was more than 95% while the discharge capacity reached 134.7 mAh.g-1 at 1 C indicating high electrochemical capacity and excellent cycling stability.