Multifunctional Elastic Supramolecular Hydrogels with Self‐Healing, Adhesive, and Ionic Thermoelectric Property for Flexible Sensing and Energy Harvesting

Supramolecular hydrogels capable of integrating mechanical robustness, strong adhesion, and reliable energy conversion remain highly sought for next‐generation soft electronics. Here, we present a transparent, ultra‐stretchable ionic hydrogel constructed through synergistic host–guest interaction, hydrogen bonding, and electrostatic interactions. The dynamic network exhibits outstanding mechanical performance (2173% strain, 340 kPa strength, 2.88 MJ m − 3 toughness), rapid self‐healing, broad‐substrate adhesion, and potent antibacterial activity. The hydrogel functions as a sensitive strain sensor with stable, multimodal motion detection. It further serves as an efficient electrode for both triboelectric and droplet‐based energy harvesting, powering commercial LEDs. Notably, the material exhibits a high p‐type ionic thermoelectric response, achieving a Seebeck coefficient of 2.95 mV K − 1 and scalable thermovoltage output up to 14.3 mV/K in modular ionic thermoelectric capacitors. This work provides a versatile materials platform toward integrated soft electronics with simultaneous mechanical, sensing, and energy harvesting functionalities.