Fully Self‐Powered Multimodal Flexible Sensors: Multi‐Mechanism Energy Conversion for Next‐Generation Wearable Electronics

ABSTRACT With the advancement of wearable devices, multimodal sensing has become increasingly pivotal for enhancing the functionality of advanced flexible sensors, while reliable energy supply remains a core challenge limiting sustainable operation. Compared to conventional strategies reliant on external power, fully self‐powered technology, an emerging approach enabling all modalities of multimodal sensors to operate without external batteries, has made breakthroughs in addressing both their sustainable use and the waste energy utilization. Therefore, it is urgent to systematically review the recent advances in fully self‐powered multimodal flexible sensors (FSMFSs). First, we comprehensively summarize mechanisms of various ambient energy harvesting technologies applied to FSMFSs, including thermoelectric, piezoelectric, and chemical electric conversion. Next, we present their collaborative application to achieve fully self‐powered operation in dual‐modal (temperature‐pressure, pressure‐light) and triple‐modal (pH‐Cl − ‐glucose) sensing. Through analyzing representative cases, we provide inspirational sights for the self‐powered technology, decoupling strategies, structural innovation, and material design of multimodal sensors. Finally, we highlight existing limitations and future development directions, aiming to promote large‐scale applications beyond laboratory innovations and offer profound guidance for FSMFS development.