Towards All‐Solid‐State Polymer Batteries: Going Beyond PEO with Hybrid Concepts

To go beyond polyethylene oxide in lithium metal batteries, a hybrid polymer/oligomer cell design is presented, where an ester oligomer provides high ionic conductivity of 0.2 mS cm−1 at 40 °C within thicker composite cathodes with active mass loadings up to 11 mg cm−2 (LiNbO3-coated) LiNi0.6Mn0.2Co0.2 (NMC622), while 30 µm thin scaffold-supported polymer electrolyte affords mechanical stability. Corresponding discharge capacities the cells exceed 170 mAh g−1 (11 cm−2) or 160 (6 rates either 0.1 0.25 C. Multilayer pouch are projected enable energy densities 235 Wh L−1 and even 356 cm−2), clearly superior other reported polymer-based designs. Polyester electrolytes environmentally benign safer compared common liquid electrolytes, straightforward synthesis affordability precursors render polyester suitable candidates for future application solid-state batteries.