过渡金属催化石墨化碳包覆LiFePO_(4)正极材料  

Transition metal catalyzed graphitized carbon coated LiFePO_(4) cathode materials

作　　者：杨桂芬 黄德权[2] 卢文斌[1] 王红强[2] 李庆余[2] YANG Guifen;HUANG Dequan;LU Wenbin;WANG Hongqiang;LI Qingyu(Shenzhen Academy of Metrology&Quality Inspection,Shenzhen Guangdong 518106,China;Guangxi Normal University,Guilin Guangxi 541004,China)

机构地区：[1]深圳市计量质量检测研究院,广东深圳518106 [2]广西师范大学,广西桂林541004

出　　处：《电源技术》2023年第12期1538-1542,共5页Chinese Journal of Power Sources

基　　金：漓江流域新能源船舶的研发及产业化示范(桂科AA18118005);汽车标准化公益性开放课题(CATARC-Z-2022-01353)。

摘　　要：橄榄石结构磷酸铁锂(LFP)作为锂离子电池正极材料已实现大规模商业化应用。然而,磷酸铁锂电子导电性和锂离子扩散率较低,导致其质量和电荷传输动力学较低,造成其电化学性能不佳。采用简单砂磨混合法成功制备了过渡金属(Fe、Co、Ni)催化石墨化碳涂层磷酸铁锂。研究结果表明,所制备材料经过渡金属(Fe、Co、Ni)催化石墨化后碳涂层均匀包覆在颗粒表面,能够有效抑制高温烧结过程中颗粒生长以及材料团聚,而不改变LFP的晶体结构。电化学性能测试结果表明,过渡金属催化石墨化碳膜涂层可以提高LFP电子导电性,缩短Li^(+)扩散路径,有效改善材料的倍率性能和循环稳定性。在电压范围2.5~4.0 V时,LFP/C-Ni可提供161.3 mAh/g@0.1 C和118.1 mAh/g@5 C的高放电比容量,2 C倍率循环200次的容量保持率仍高达99.1%。Olivine structured lithium iron phosphate(LFP)as cathode material of lithium ion batteries has achieved large-scale commercial application.However,lithium iron phosphate has low electronic conductivity and lithium ion diffusivity,leading to lower mass and charge transport kinetics,resulting in poor electrochemical performance.In this paper,a kind of LFP/C cathode material coated with transition metal(Fe,Co,Ni)catalyzed graphitized carbon was successfully prepared by a simple sanding mixing method.The results show that transition metals(Fe,Co,Ni)catalyzed graphitized carbon is not only uniformly coated on the surface of LFP/C particles,but also effectively inhibits the particle growth and agglomeration during high sintering process and without changing the crystal structure of LFP.The electrochemical performance test results indicate that the transition metal catalyzed graphitized carbon film coating can improve the electronic conductivity of LFP,shorten the Li^(+)diffusion path,and effectively improve the rate performance and cycling stability of the materials.In the voltage range of 2.5 V to 4.0 V,LFP/C-Ni can provide high discharge specific capacity of 161.3 mAh/g at 0.1 C and 118.1 mAh/g at 5 C,with 99.1%retained initial capacitance after 200 cycles at 2 C rate.

关 键 词：锂离子电池 正极材料 电化学性能 催化石墨化 LFP/C-Ni 

分 类 号：TM912.9[电气工程—电力电子与电力传动]