Towards Lithium-Sulfur Batteries for Aerospace Applications by means of Firedrake

Abstract

The transformation of the European energy sector to more efficient and sustainable technologies is a matter of utmost importance in the face of climate change. However, considering the fact that renewable energy sources are inherently volatile, the development of novel and innovative electrochemical storage systems 'calming the waves' of volatility has become a very active research area. Along with these efforts and the prospect of large electric energy storages, the interest in battery-powered aerospace applications has also grown. The full potential of novel battery types in one of the most demanding engineering environments, in which energy, power, and weight requirements must be jointly met at the same time, is yet still unclear. Lithium-sulfur batteries as conversion type batteries are currently believed to be one of the most promising candidates due to their exceptionally high theoretical gravimetric energy density, being just a quarter of kerosene burnt in civil aero-engines. However, there is already empirical evidence that building cells with high gravimetric energy density and power density is conflicting due to kinetic limitations and, hence, contrary to kerosene-based propulsion. To exactly pin down this optimum, which is also believed to depend on the microstructure of the porous cathode, is challenging, even for cutting-edge experimental operando methods. Therefore, we have developed a 3D scale-resolving Firedrake framework as a complementary 'numerical operando technique', which aims at narrowing the optimization window and helping to find the most relevant parameters controlling the multi-scale transport process in the porous structure. The locally coarse-grained continuum model is currently solved using a DG0 approach in combination with an adaptive time-stepping procedure, which will be presented alongside with first vivid insights into the nonlinear transport process.