Investigating Diffusion of Lithium Intercalated in Graphite By a Combination of Multiscale Modeling and NMR

摘要

Lithium ion batteries play a key role in the implementation of fully sustainable electrical mobility. Long lifetime, fast recharging and safety are required for the acceptance of any battery powered vehicle. Graphite is still the state of art as negative electrode. Despite decades of investigation into the mechanism of lithium intercalation, the ion mobility and the underlying microscopic processes are still not fully understood, limiting progress in performance and lifetime prediction of a battery. In particular, improvements in fast charging of batteries mandates a deeper understanding of the lower states of charge (SoC), bellow or around 20%. We propose a combination of advanced NMR experiments, i.e spin alignment echo (SAE), with a theoretical multi scale modelling approach to investigate relevant phenomena such as lithium ion diffusion in graphite. Here, we present a novel multi-level accelerated first-principles kinetic Monte Carlo (1p-kMC) model to assess in detail the mobility at a low SoC, i.e LiC_(108). In particular, an external potential is applied in order to mimic the driving force causing (dis)charge of the battery.