Pouch Versus Press Cells—How Cell Configuration Dictates Low-Pressure Performance in Sulfide Solid-State Batteries

Impressive electrochemical performance has been demonstrated with sulfide-based solid-state batteries. However, these results are predominantly obtained under high stack pressures—up to hundreds of MPa. While such conditions are valuable for probing fundamental material properties and intrinsic performance limits, the resulting cell metrics are not easily transferable to practical applications. Consequently, there is a growing imperative for application-oriented evaluation of SSBs under more realistic, low-pressure conditions in the single-digit MPa range. In this study, we demonstrate that the assessment of low-pressure performance can be significantly influenced by the chosen cell architecture. By comparing the cycling performance of sulfide-based SSBs—utilizing an NMC composite cathode and an In/(InLi)$_x$ anode with argyrodite-type Li$_6$PS$_5$Cl as electrolyte—in both pouch-cell and press-cell configurations, we reveal significant discrepancies in electrochemical performance at stack pressures ranging from 0 MPa to 25 MPa. Notably, the developed pouch cells exhibit superior electrochemical performance at low stack pressures of 1 MPa compared to their press-cell counterparts despite the same materials used. ... mehrUsing three-electrode pouch cells, we identify In/(InLi)$_x$ anode delamination as a primary low-pressure failure mechanism. Overall, our findings emphasize that a realistic assessment of SSB cell performance requires cell architectures that mirror targeted applications.