Multi-Scale Modelling of Battery Materials, Structures, and Dynamics

In view of climate change and fossil fuel depletion it is evident that humanity needs to transition from a fossil fuel based economy to one based on renewable energies. Yet, this process is hampered by insufficient and inadequate (for e.g. mobility applications) alternate energy storage solutions. All-solid-state batteries, based on solid-state electrolytes (SSE), currently receive lots of attention due to their potentially high energy densities and stability. Yet, they suffer from very low power densities due to limited charge carrier transport across the interface with the electrodes. 

Based on density-functional (DFT) property calculations for simplified models and classical molecular dynamics (MD) simulations with standard, polarizable, and variable charge force-fields we construct full multi-scale kinetic Monte-Carlo (kMC) models of the charge carrier dynamics in all-solid-state batteries incorporating structural and dielectric properties of the material at hand as well as the concentration of dopants and defects. Using these models we study the formation of charge carrier blocking layers in the electrolyte at open circuit conditions explaining the relatively poor performance of current SSE based devices. Furthermore, we investigate techniques currently discussed as a possible remedy, such as introduction of spacer layers between SSE and electrodes, and their effect on the expected device performance.