Berlin 2015 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 23: Methods in Computational Materials Modelling: Battery Mateirals
MM 23.4: Talk
Tuesday, March 17, 2015, 12:30–12:45, H 0106
Phase field modeling of Li-insertion kinetics in single LiFePO4- nano-particles for rechargeable Li-ion battery application — •Michael Fleck, Holger Federmann, Philipp Amendt, and Heike Emmerich — Materials and Processsimulation, University of Bayreuth
LiFePO4 is widely considered to be a promising cathode material for Li-ion rechargeable batteries. The lithiation process in LiFePO4 nano-particles proceeds via a coherent solid-solid phase transformation between the LiFePO4 (LFP-phase) and FePO4 (FP-phase). We develop a continuum phase field model for solid-solid phase transformations in single-LiFePO4-nano-particles, embedded in an elastically soft electrolyte-phase. The model-description explicitly includes anisotropic (orthorhombic) and inhomogeneous elastic effects, resulting from coherency strain, as well as anisotropic (1D) Li-diffusion insight the nano-particles. The moving LFP/FP-phase boundary is modeled as a diffuse interface of finite. Here, with the inclusion of the elastically soft electrolyte-phase, we consider also non-rectangular shaped LiFePO4- particles in a fully anisotropic 3D-framework. The resulting model is employed to investigate effects of the nano-particle’s size and shape on the kinetics of FP to LFP phase transformations, relating to single particle charge rates.