Modeling the Effects of Pressure on Solid-State Lithium–Sulfur Batteries

All-solid-state lithium–sulfur batteries (ASLSBs) offer a superior alternative to traditional lithium-ion batteries, given their potential for higher energy densities and enhanced safety. This article explores ASLSBs under controlled stress and constant-strain scenarios, develops data-driven models that predict cell voltage given input current, and correlates observations with cell states. The empirical data collected under varying operational pressure conditions are used to perform system identification of equivalent circuit model parameters that account for variations in the externally applied force resulting from dynamic operational pressure. Cell capacity fades rapidly, but analysis reveals correlations between usable energy, cell impedance, and applied pressure. Most notable are observations of capacity recovery, which show that reduced capacity due to operations at lower pressure is reversible. This work also demonstrates that variations in battery stress over time in a constant volume provide a means to estimate the cell’s state of charge. This study highlights the crucial role of pressure in enhancing the performance of ASLSBs.