Chin.J.Chem.Eng. ›› 2012, Vol. 20 ›› Issue (4): 793-802.

• MATERIALS AND PRODUCT ENGINEERING • Previous Articles     Next Articles

Response surface optimization for process parameters of LiFePO4/C preparation by carbothermal reduction technology

YANG Kedi, TAN Fangxiang, WANG Fan, LONG Yunfei, WEN Yanxuan   

  1. School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
  • Received:2011-02-19 Revised:2011-10-11 Online:2011-10-11 Published:2012-08-28

响应面法优化碳热还原合成LiFePO4/C的工艺参数

杨克迪, 谭芳香, 王凡, 龙云飞, 文衍宣   

  1. School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China

Abstract: A statistically based optimization strategy is used to optimize the carbothermal reduction technology for the synthesis of LiFePO4/C using LiOH, FePO4 and sucrose as raw materials. The experimental data for fitting the response are collected by the central composite rotatable design (CCD). A second order model for the discharge ca-pacity of LiFePO4/C is expressed as a function of sintering temperature, sintering time and carbon content. The ef-fects of individual variables and their interactions are studied by a statistical analysis (ANOVA). The results show that the linear effects and the quadratic effects of sintering temperature, carbon content and the interactions among these variables are statistically significant, while those effects of sintering time are insignificant. Response surface plots for spatial representation of the model illustrate that the discharge capacity depends on sintering temperature and carbon content more than sintering time. The model obtained gives the optimized reaction parameters of sinter-ing temperature at 652.0 ?C, carbon content of 34.33 g•mol?1 and 8.48 h sintering time, corresponding to a dis-charge capacity of 150.8 mA•h•g?1. The confirmatory test with these optimum parameters gives the discharge ca-pacity of 147.2 and 105.1 mA•h•g?1 at 0.5 and 5 C, respectively.

Key words: lithium ion battery, cathode material, lithium iron phosphate, carbothermal reduction technology, response surface methodology

摘要: A statistically based optimization strategy is used to optimize the carbothermal reduction technology for the synthesis of LiFePO4/C using LiOH, FePO4 and sucrose as raw materials. The experimental data for fitting the response are collected by the central composite rotatable design (CCD). A second order model for the discharge ca-pacity of LiFePO4/C is expressed as a function of sintering temperature, sintering time and carbon content. The ef-fects of individual variables and their interactions are studied by a statistical analysis (ANOVA). The results show that the linear effects and the quadratic effects of sintering temperature, carbon content and the interactions among these variables are statistically significant, while those effects of sintering time are insignificant. Response surface plots for spatial representation of the model illustrate that the discharge capacity depends on sintering temperature and carbon content more than sintering time. The model obtained gives the optimized reaction parameters of sinter-ing temperature at 652.0 ?C, carbon content of 34.33 g•mol?1 and 8.48 h sintering time, corresponding to a dis-charge capacity of 150.8 mA•h•g?1. The confirmatory test with these optimum parameters gives the discharge ca-pacity of 147.2 and 105.1 mA•h•g?1 at 0.5 and 5 C, respectively.

关键词: lithium ion battery, cathode material, lithium iron phosphate, carbothermal reduction technology, response surface methodology