Beta-Cyclodextrin as Carbon Source for Synthesis of LiFePO_4/C with Improved Electrochemical Properties in Lithium-ion Batteries  

作　　者：赖春艳 赵家昌 解晶莹 

机构地区：[1]Shanghai Institute of Microsystem and Information Technology, Shanghai 200050, China , Graduate School, the Chinese Academy of Sciences, Beijing 100049, China [2]Shanghai Institute of Microsystem and Information Technology, Shanghai 200050, China

出　　处：《Journal of Rare Earths》2005年第S1期219-223,共5页稀土学报（英文版）

基　　金：ProjectsupportedbyNationalNatureScienceFoundationofChina(50172058)

摘　　要：For beta-cyclodextrin (β-CD) may form complexes with metal ions during ballmilling process, it was used as a novel carbon source to synthesize LiFePO_4/C cathode composite in lithium-ion batteries via solid-state reaction. This composite should has fine particle size and good electrochemical performances. The powders were characterized by XRD, SEM, TEM and galvanostatic charge-discharge. Compared with bare LiFePO_4 and LiFePO_4/C composite with glucose as carbon source by the same procedure and nearly the same content of carbon in the final cathode, the LiFePO_4/C composite with beta-cyclodextrin as carbon source shows much higher discharge specific capacity and more excellent rate performance. Ultrasonic dispersion between ballmilling and sinter process for 2 h was appropriate and useful for final LiFePO_4/C to reach higher discharge capacity. The SEI experiment was carried out to explore the effect of beta-cyclodextrin on the cathode materials, and the results indicate that coating with beta-cyclodextrin can improve the electrochemical performance of LiFePO_4 by decreasing the resistance of charge transfer (R_ ct) and improving the chemical diffusion coefficient (D_ Li).For beta-cyclodextrin (β-CD) may form complexes with metal ions during ballmilling process, it was used as a novel carbon source to synthesize LiFePO_4/C cathode composite in lithium-ion batteries via solid-state reaction. This composite should has fine particle size and good electrochemical performances. The powders were characterized by XRD, SEM, TEM and galvanostatic charge-discharge. Compared with bare LiFePO_4 and LiFePO_4/C composite with glucose as carbon source by the same procedure and nearly the same content of carbon in the final cathode, the LiFePO_4/C composite with beta-cyclodextrin as carbon source shows much higher discharge specific capacity and more excellent rate performance. Ultrasonic dispersion between ballmilling and sinter process for 2 h was appropriate and useful for final LiFePO_4/C to reach higher discharge capacity. The SEI experiment was carried out to explore the effect of beta-cyclodextrin on the cathode materials, and the results indicate that coating with beta-cyclodextrin can improve the electrochemical performance of LiFePO_4 by decreasing the resistance of charge transfer (R_ ct) and improving the chemical diffusion coefficient (D_ Li).

关 键 词：LiFePO_4/C cathode composite BETA-CYCLODEXTRIN solid-state reaction ultrasonic dispersing coating 

分 类 号：TM911[电气工程—电力电子与电力传动]