聚羧酸对LiFePO_4正极材料结构和性能的影响  

Effect of Polycarboxylate on Structure and Performance of LiFePO_4 Cathode Material

作　　者：莫祥银[1] 冯晓叁[1] 俞琛捷[1] 丁毅[2] 康彩荣[2] 倪聪[2] 

机构地区：[1]南京师范大学分析测试中心,江苏南京210046 [2]南京工业大学材料科学与工程学院,江苏南京210009

出　　处：《南京师大学报（自然科学版）》2012年第1期58-62,共5页Journal of Nanjing Normal University(Natural Science Edition)

基　　金：国家"973"项目(6134501ZT01-004-02);江苏省自然科学基金项目(2007191SB90098);德意志学术交流基金项目(DAAD Section 423-China;Mongolia)

摘　　要：为了改善磷酸铁锂的电化学性能,以碳酸锂、草酸亚铁、磷酸二氢铵为原料,聚羧酸为碳源,用两步球磨高温固相法合成了锂离子电池正极LiFePO4/C复合材料.讨论了聚羧酸含量对LiFePO4/C的结构和性能的影响.一方面,用X射线衍射、扫描电子显微镜/X-射线能谱仪等方法研究了聚羧酸对LiFePO4/C晶体结构和表面形貌的影响.另一方面,用电化学方法研究了聚羧酸对LiFePO4/C的充放电性能和循环稳定性的影响.研究结果表明:聚羧酸作为碳源包覆合成的LiFePO4/C具有单一的橄榄石结构,颗粒大小均匀,具有良好的电化学性能和循环稳定性.其中,加入聚羧酸量为10wt.%的样品表现出最好的电化学性能,在0.1C下首次放电比容量为130.6 mAh/g.In order to improve the electrochemical performance of LiFePO4,LiFePO4/C cathode material was synthesized for lithium rechargeable batteries by two step ball-milling and high temperature solid-state reaction,using Li2CO3,FeC2O4·2H2O,（NH4）2HPO4 as raw materials and polycarboxylate as carbon source.The effect of different contents of polycarboxylate on the structure and performance of the samples was discussed.On the one hand,the effect of polycarboxylate on crystal structure and surface morphology of LiFePO4/C composite material was investigated by using X-ray diffraction,and scanning electron microscope/X-ray energy dispersive spectroscopy.On the other hand,electrochemical measurements were used to study the effect of polycarboxylate on charge/discharge performance and cycle stability of LiFePO4/C composite material.The results indicated that the prepared samples by coating polycarboxylate had single olivine structures and uniform particle sizes,and exhibited excellent electrochemical performances and enhanced stabilities.Among them,the product with polycarboxylate content of 10wt.% showed the best specific discharge capacity and cycle performance,and its first specific discharge capacity was 130.6 mAh/g at 0.1C.

关 键 词：锂离子电池 正极材料 LIFEPO4 聚羧酸 包覆 

分 类 号：TM912.9[电气工程—电力电子与电力传动]