Synergistic dual supramolecular interactions enhance ionic thermoelectric performance in dilute-electrolyte hydrogels

• • Achieved a thermopower of 2.21 mV/K at a low iodine concentration of 10 mmol/L I− + 2.5 mmol/L I3−, representing a tenfold enhancement in peak power output compared to controls, enabling efficient low-grade heat harvesting from the human body (~32°C). • • The dual supramolecular interactions (host-guest complexation of α-CD with I3− and hydrogen bonding with PVA) are critical for the high thermopower, as they enhance the Seebeck coefficient without requiring high ionic concentrations, mitigating toxicity and corrosion issues. • • The hydrogel exhibits excellent biocompatibility and mechanical robustness, suitable for direct skin contact, as demonstrated by flexible devices generating nearly 100 mV from body heat, which is sufficient for powering wearable sensors. • • The sensor arrays demonstrate motion and spatial temperature sensing capabilities, indicating potential for personalized healthcare monitoring and human-computer interfaces, with the low ionic concentration addressing safety concerns for prolonged wear.