物理化学学报 >> 2013, Vol. 29 >> Issue (11): 2361-2370.doi: 10.3866/PKU.WHXB201309032

电化学和新能源 上一篇    下一篇

LiCoO2电池正极微结构重构及有效传输系数预测

吴伟1,2, 蒋方明1, 曾建邦1   

  1. 1 中国科学院广州能源研究所先进能源系统实验室, 中国科学院可再生能源重点实验室, 广州 510640;
    2 中国科学院大学, 北京 100049
  • 收稿日期:2013-06-28 修回日期:2013-09-02 发布日期:2013-10-30
  • 通讯作者: 蒋方明 E-mail:jiangfm@ms.giec.ac.cn
  • 基金资助:

    国家自然科学基金(51206171)和中科院“百人计划”资助项目

Reconstruction of LiCoO2 Cathode Microstructure and Prediction of Effective Transport Coefficients

WU Wei1,2, JIANG Fang-Ming1, ZENG Jian-Bang1   

  1. 1 Laboratory of Advanced Energy Systems, CAS Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, P. R. China;
    2 University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2013-06-28 Revised:2013-09-02 Published:2013-10-30
  • Contact: JIANG Fang-Ming E-mail:jiangfm@ms.giec.ac.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51206171) and CAS“100 Talents”Program.

摘要:

采用MonteCarlo方法重构了LiCoO2电池正极的三维微结构,重构单元的特征尺寸为几十纳米量级,从而得到了明确区分活性材料、固体添加物以及孔相(电解液)的微结构.通过对重构电极的特征化分析,得到了微结构中特定相的连通性和扭曲率、组分体积分数的空间分布、比表面积、孔径分布等特征信息.采用D3Q15格子Boltzmann模型(LBM)计算了该重构电极的有效热导率、电解液(或固相)的有效传输系数.同时发现,与随机行走方法以及Bruggemann关系式计算获得的扭曲率数值相比,LBM预测值更可靠.

关键词: 锂离子电池孔尺度模型, 微结构重建, Monte Carlo方法, 特征化, 扭曲率, 有效传输系数, 格子Boltzmann方法, 随机行走方法

Abstract:

Understanding the impact of microstructure of lithium-ion battery electrodes on performance is important for the development of relevant technologies. In the present work, the Monte Carlo Ising model was extended for the reconstruction of three-dimensional (3D) microstructure of a LiCoO2 lithium-ion battery cathode. The electrode is reconstructed with a resolution on the scale of 50 nanometers, which allows three individual phases to be evidently distinguished: LiCoO2 particles as the active material, pores or electrolyte and additives (polyvinylidene fluoride (PVDF) + carbon black). Characterization of the reconstructed cathode reveals some important structural and transport properties, including the geometrical connectivity and tortuosity of specific phases, the spatial distribution and volume fractions of specific phases, the specific surface area, and the pore size distribution. A D3Q15 lattice Boltzmann model (LBM) was developed and used to calculate the effective thermal conductivity and the effective transport coefficient of the electrolyte (or solid) phase. It is found that tortuosity values determined by LBMare more reliable than those predicted by the random walk simulation or the Bruggeman equation.

Key words: Pore-scale modeling to lithium-ion battery, Microstructure reconstruction, Monte Carlo approach, Characterization, Tortuosity, Effective transport coefficient, Lattice Boltzmann method, Random walk method

MSC2000: 

  • O641