Design and Validation of Anode-Free Sodium-Ion Pouch Cells Employing Prussian White Cathodes

This study investigated the impact of pouch cell design on energy density, both volumetric and gravimetric, through the development of accurate 3D models of small-format (<5 Ah) pouch cells. Various configurations were analysed, considering material properties and extrapolating expected electrochemical performance from studies on Prussian white cathodes in coin and pouch cells. This approach allowed for a rapid assessment of several performance-influencing factors, including the number of layers in the pouch cell, cathode thickness, active material percentage, and electrolyte volume. The highest calculated energy density of small-format pouch cells was shown to be 282 Wh kg−1 and 454 Wh L−1, achieved in a 3 Ah, 20-layer pouch cell. The calculations were validated using sodium-ion anode-free pouch cells utilising a Prussian white cathode in single- and few-layer format pouch cells (<0.1 Ah) cycled under a low external pressure (~200 kPa).