Phase-field modeling of diffusional phase behaviors of solid surfaces: A case study of phase-separating LiXFePO4 electrode particles

Tae Wook Heo, Long Qing Chen, Brandon C. Wood

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Abstract We present a comprehensive phase-field model for simulating diffusion-mediated kinetic phase behaviors near the surface of a solid particle. The model incorporates elastic inhomogeneity and anisotropy, diffusion mobility anisotropy, interfacial energy anisotropy, and Cahn-Hilliard diffusion kinetics. The free energy density function is formulated based on the regular solution model taking into account the possible solute-surface interaction near the surface. The coherency strain energy is computed using the Fourier-spectral iterative-perturbation method due to the strong elastic inhomogeneity with a zero surface traction boundary condition. Employing a phase-separating LiXFePO4 electrode particle for Li-ion batteries as a model system, we perform parametric three-dimensional computer simulations. The model permits the observation of surface phase behaviors that are different from the bulk counterpart. For instance, it reproduces the theoretically well-established surface modes of spinodal decomposition of an unstable solid solution: the surface mode of coherent spinodal decomposition and the surface-directed spinodal decomposition mode. We systematically investigate the influences of major factors on the kinetic surface phase behaviors during the diffusional process. Our simulation study provides insights for tailoring the internal phase microstructure of a particle by controlling the surface phase morphology.

Original languageEnglish (US)
Article number6434
Pages (from-to)323-332
Number of pages10
JournalComputational Materials Science
Volume108
DOIs
StatePublished - Oct 1 2015

    Fingerprint

All Science Journal Classification (ASJC) codes

  • Computer Science(all)
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Computational Mathematics

Cite this