3D‐Printed Flexible Microliquid Metal Supercapacitors and Their Energy Storage Characteristics

The growing demand for wearable devices has created an urgent need for flexible, high‐energy‐density micropower sources, traditional supercapacitors, which are limited by brittle materials and high‐risk liquid electrolytes, struggle to meet this challenge. To overcome the limitations in flexibility and energy density of conventional supercapacitors and address the power supply requirements of wearable electronics, this study employs 3D printing technology to fabricate an integrated flexible microsupercapacitor using liquid metal as the core electrode. The device combines an EGaIn eutectic alloy with a polymer electrolyte, utilizing a composite system comprising a flexible PET substrate and liquid metal–PVA/epoxy electrolyte. It achieves both a high volumetric energy density of 16.0 mWh/cm 3 and outstanding mechanical robustness, maintaining 92% capacitance retention after 5000 bending cycles. Through in‐depth mechanistic investigation, a synergistic enhancement effect in interfacial charge storage was revealed. This work not only systematically optimizes the manufacturing process but also elucidates the synergistic energy storage mechanism via in situ electrochemical analysis, paving the way for innovative power solutions in flexible electronics and providing practical theoretical guidance and technical strategies for realizing high‐performance, highly reliable miniaturized power systems.