Bridging Performance and Fate: A Framework for Sustainable, Composite‐Based Flexible Electronic Systems

Flexible electronics are increasingly used in wearable devices, implantable systems, soft robotics, and disposable sensors, raising concerns regarding the environmental accumulation of electronic materials. Conventional electronic materials provide high electrical performance and mechanical robustness but resist degradation, whereas biodegradable polymers often lose functionality before the end of device operation. This review introduces a performance–fate framework in which polymer chemistry, composite architecture, interfacial engineering, and multilayer device design are co‐optimized to balance operational stability with controlled degradation. Recent studies demonstrate that biodegradable polymer composites can achieve conductivities approaching 55 S m −1 while maintaining mechanical flexibility, whereas ionic‐gated transistors enable low‐power operation at 0.5–2 V with leakage currents below 10 −7 A cm −2 . In parallel, degradable polymers such as poly(lactic‐co‐glycolic acid) (PLGA) exhibit tunable degradation kinetics that define practical device lifetimes. By correlating electrical transport, mechanical reliability, corrosion behavior, and hydrolysis kinetics with filler networks, interfacial interactions, crystallinity, and moisture diffusion, this review establishes composite‐based design principles for sustainable flexible electronics with predictable end‐of‐life behavior.