Berlin 2018 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 2: Battery Materials
MM 2.5: Talk
Monday, March 12, 2018, 11:15–11:30, H 0106
First-principles approach to lithium diffusion in silicon — •Vishank Kumar, Davide Di Stefano, Gian-Marco Rignanese, and Xavier Gonze — Institute for Condensed Matter and Nanosciences, European Theoretical Spectroscopy Facility, Université Catholique de Louvain, Chemin des étoiles 8, B-1348 Louvain-la-Neuve, Belgium
The high lithium storing capacity of silicon has drawn a strong interest for its possible application as an anode material in Li-ion batteries. However, the kinetics of lithium diffusion in silicon and in other lithiated phases of silicon, are not yet fully understood. In this study, the transition state theory was used to calculate the temperature dependent diffusion coefficient of Li, in bulk Si and LiSi phase. Quantum mechanical effects were also considered via semi-classical transition state theory. The energy barriers and pre-exponential factors have been obtained from total energy and phonon calculations, respectively, using the density functional theory (DFT). Kinetic Monte Carlo (KMC) simulations were used to calculate the effective diffusion coefficient in LiSi case with multiple vacancy mediated diffusion pathways.
Our results are in good agreement with the experimental data and suggest that quantum mechanical effects are only marginally significant in Li-Si system. The current study shows a theoretical approach, which is computationally efficient and quantitatively accurate, to fill the lack of studies on Li diffusion in lithiated LixSi phases.