Batteries play a key role in the current transformation of our global energy system. Renewables cause significant fluctuations in energy production. Consequently, one currently observes a very volatile electricity market and even negative electricity prices. This recently attracted tremendous interest in utility-scale battery storage solutions. The market is currently dominated by Lithium-Ion batteries (LIBs). However, due to the geopolitical situation alternatives to current LIB technology with resilient supply chains, such as Sodium-Ion Batteries (SIBs) gain importance. The key to enable new battery chemistries is the development of novel active materials (AMs). Typically, AMs are polycrystalline materials consisting of primary particles with varying internal porosity. Geometrical properties and the morphology of the particles determine their electrochemical performance. Particularly, transport processes in the materials and on the surface of the materials affect the rate performance and storage mechanism. In order to further advance the technology, a good understanding of individual transport processes as well as their interplay is necessary. Despite the relevance of properties on the particle level, only few approaches are discussed in the literature [1]. In our contribution we will present our latest results on the modeling and simulation of LIB and SIB materials on the particle scale. On the one hand we will present simulations resolving the internal particle structure. Based on this approach different particle properties can be linked to interior dynamics and, consequently, to particle performance via simulations with varying 3D particle microstructures. On the other hand, we will present results of our novel framework enabling simulation of transport processes on exterior and interior particle surfaces [2]. This opens up new avenues in the detailed simulation of AM particles, such as transport along grain boundaries or the nucleation and deposition of metallic secondary phases. REFERENCES [1] J. M. Allen et al. “Quantifying the influence of charge rate and cathode-particle architectures on degradation of Li-ion cells through 3D continuum-level damage models” J. Power Sources, 512, 230415 (2021). [2] Gerhard Dziuk and Charles M. Elliott, “Finite element methods for surface PDEs” Acta Numerica, 22, pp. 289 – 396 (2013).