Photocatalytic‐Filler‐Engineered Solid Polymer Electrolytes for High‐Performance Flexible Lithium‐Metal Batteries

Flexible all‐solid‐state energy storage devices, with their exceptional energy density and safety, have emerged as promising candidates for next‐generation portable electronics. However, the development of solid polymer electrolytes (SPEs) that simultaneously achieve high ionic conductivity, mechanical resilience, and interfacial stability remains a significant challenge. Although incorporating functionalized inorganic fillers into polymer matrices has shown partial success in enhancing ion transport, the intrinsic limitations of traditional fillers—low room‐temperature ionic conductivity—hinder their further application. To address this, a novel strategy inspired by photocatalytic design principles is proposed, which involves engineering photocatalytic active fillers to generate strong and stable photogenerated electric fields. These fields modulate interfacial charge distribution, promote segmental motion of polymer chains, and facilitate lithium (Li) salt dissociation, while simultaneously optimizing the Li + solvation structure and coordination environment. Importantly, this approach significantly minimizes anion recombination, effectively suppressing space charge layer formation and reducing Li + concentration gradients. This innovative concept provides a new approach for developing high‐performance flexible lithium metal batteries.