From microstructure to performance through coupled electrochemical and mechanical insights in all-solid-state batteries

초록

All-solid-state batteries (ASSBs) are promising next-generation energy storage systems, however, their performance and mechanical reliability are strongly influenced by electrode microstructure. While continuum-scale models such as pseudo-2D (P2D) approaches are widely used, they inherently rely on averaged structural parameters, potentially overlooking critical local heterogeneities. Here, we systematically examine the limitations of averaged modeling by comparing P2D full-cell simulations with microstructure-resolved 2D slice-based halfcell analyses derived from statistically generated model microstructures. Controlled microstructures with varying particle sizes and volume fractions are employed to investigate how structural features influence electrochemical and mechanical responses. The results show that the P2D model, even when incorporating physically informed average contact areas, does not fully capture localized transport limitations and reaction heterogeneity. In contrast, the slice-based analysis reveals that cross-sectional tortuosity gradients are associated with localized transport bottlenecks, leading to significant variations in lithium-ion concentration and current distribution. Furthermore, non-uniform particle arrangements induce localized stress accumulation, which cannot be predicted from averaged descriptors alone. These findings indicate that local microstructural variations, rather than bulk-averaged properties alone, can influence local electrochemical response and stress development in ASSBs.

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