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 stabilit...