【作者】 孙福根； 刘爽； 凌立成； 龙东辉；

【Author】 SUN Fu-Gen,LIU Shuang,LING Li-Cheng,LONG Dong-Hui (State Key Laboratory of Chemical Engineering,East China University of Science and Technology,Shanghai 200237, China)

【机构】 华东理工大学化学工程联合国家重点实验室；

【摘要】 采用芳香性水杨酸作为辅助剂,固相合成了高性能纳米LiFePO₄/C电极材料.煅烧过程中,水杨酸在颗粒表面形成均匀的覆层,有效抑制了LiFePO₄颗粒的生长.同时,水杨酸由于其芳香特性,更容易裂解成高石墨化的碳层,从而提供更高的电导率.水杨酸的添加量对产物的颗粒尺寸,含碳量和电化学性能具有明显的影响.当添加75 wt.%的水杨酸时,制得的LiFePO₄/C复合材料具有均一的纳米级颗粒尺寸70-100 nm和1-2 nm厚的原位包覆碳层.该材料作为锂离子电池正极材料时,具有很高的可逆容量和循环稳定性,并且具有很好的倍率性能。这种简单高效的合成方法,有望批量生产高性能LiFePO₄正极材料更多还原

【Abstract】 High performance nanocrystalline LiFePO₄/C was successfully synthesized via solid-state method assisted with aromatic salicylic acid.Salicylic acid forms a uniform in situ capping layer on the particle surface,which effectively suppress the growth of LiFePO₄ particles due calcinations.Due to its aromatic characteristic,salicylic acid is easily pyrolyzed into highly graphited carbon layer to provide high electronic conductivity.The addition amount of salicylic acid has a significant effect on particle size,carbon content and electrochemical performance of the final products. With 75 wt.%salicylic acid added in the precursors,the prepared LiFePO₄/C composite has homogenous nanometer particles with about 70-100 nm size and uniform in situ carbon coating with about 1-2 nm thickness.When used as the cathode material,the prepared material exhibits a high revisable capacity（154 mAh/g at 0.2 C） and good cycle stability,as well as excellent rate performance.This method is simple and efficient,making it on the verge of being employed in large-scale LiFePO₄ production.更多还原