Development and Applications of Polymer Electrolytes in Flexible Solid-State Energy Storage Devices

Abstract Against the backdrop of swiftly evolving flexible electronics and wearable device technologies, polymer electrolytes are increasingly recognized as pivotal materials for safe and high-performance solid-state battery systems. This review systematically summarizes the recent progress in solvent-free polymer electrolytes, gel polymer electrolytes, and composite polymer electrolytes, focusing on their ion conduction mechanisms, performance optimization strategies, and applications in flexible energy storage systems. The unique advantages of polymer electrolytes, such as high safety, flexibility, and processability, are highlighted, along with critical challenges in ionic conductivity, mechanical strength, and interface compatibility. Emerging applications in supercapacitors, wearable electronics, and medical devices are discussed, emphasizing the importance of multi-scale structural design and interdisciplinary innovation. Future perspectives include the integration of dynamic bionic design, in-situ characterization, 3D printing, and artificial intelligence-driven material screening to address current bottlenecks, paving the way for next-generation flexible energy storage technologies.