Synergistic Miniaturization of Micro-Supercapacitors, Micro-Flexible Batteries, and Triboelectric Nanogenerators for Wearable Electronics

The rapid advancement of flexible and wearable electronic devices demands miniaturized, highly flexible, and safe energy storage solutions. Traditional rigid energy storage devices cannot meet the mechanical flexibility, energy density, safety, and integration compatibility requirements of wearable systems. This review systematically summarizes recent progress in three miniaturized energy storage technologies: micro-supercapacitors (MSCs), micro-flexible batteries (MFBs), and nanogenerators (NGs). We focus on three core challenges: balancing energy and power density, achieving synergy between mechanical flexibility and electrochemical stability, and enhancing environmental adaptability with system integration. Key technical routes for each device type are discussed from the perspectives of electrode material optimization, electrolyte innovation, flexible configuration design, interface engineering, and energy conversion mechanisms. Current research bottlenecks—including limited energy density, poor interface stability, and insufficient system integration—are identified. Finally, we present development trends toward multifunctional integration, intelligent response, and green sustainability. Unlike previous reviews that focus on a single device type, this work provides a comparative analysis of all three technologies and proposes an integrated “harvest–buffer–store” self-powered framework. This review provides theoretical support and technical references for next-generation self-powered flexible electronic systems.