Direct‐ink‐writing of all‐solid‐state batteries with solvent‐free, non‐flammable electrolytes toward wearable electronics

Abstract As demand for customized wearable electronics grows, free‐form Li‐ion batteries (LIBs) are attracting significant attention. Although substantial advancements have been made in printed LIBs for shape‐versatile electronics, the development of printable solid‐state electrolytes remains challenging due to the difficulty of simultaneously achieving desirable rheological properties and ionic conductivity. In this study, a solvent‐free, non‐flammable solid polymer electrolyte (SPE) is designed as a novel three‐dimensional (3D) printable electrolyte via direct ink writing (DIW) for all‐solid‐state batteries (ASSBs). The solvent‐free nature of this SPE eliminates post‐annealing steps, enhancing safety by mitigating risks of leakage, short‐circuiting, and fire. Additionally, precise control over polymer molecular weight and electrolyte composition enables high printing resolution (~100 μ…