Upscaling Sodium‐Ion Battery Cells: From Aqueous Processing to Performance Assessment of Hard Carbon|Prussian White Pouch Cells

Abstract Sodium‐ion batteries (SIBs) are a promising emerging battery technology, yet achieving competitive cycle life, energy density, and cost remains critical, particularly as LiFePO 4 /graphite cells price continues to decline. Conventional cathode manufacturing relies on fluorinated binders and toxic solvents, such as polyvinylidene fluoride and N‐methyl‐2‐pyrrolidone, raising environmental and recycling concerns and limiting overall sustainability. Water‐based electrode processing offers a greener alternative, but adoption for SIBs has been hindered by the moisture sensitivity of key cathode chemistries, including layered oxides and Prussian Blue Analogues. Here, an aqueous processing route for hard carbon (HC) anodes and Prussian White (PW) cathodes is reported, enabling pilot‐scale electrode production. Despite PW's low cost, facile synthesis, and high theoretical capacity, its pronounced sensitivity to water limits its practical implementation. This is addressed by systematically optimizing dehydration protocols, electrode formulations, and microstructure, producing defect‐free electrodes for ≈1 Ah pouch cells. The resulting cells exhibit stable cycling across varied temperatures, discharge rates, and storage conditions, achieving energy densities approaching industrial benchmarks. These results show that controlled manufacturing can address the dehydration challenges of PW, producing high‐performance, environmentally sustainable electrodes. This study establishes a practical route for scalable, pilot‐line production of HC|PW sodium‐ion cells, demonstrating the feasibility of sustainable SIB manufacturing.