(751e) Gill-Structured Composites for Sustainable Energy Collection and Self-Powering Wearable Devices

Thermoelectricity fills the niche market of long-term energy supply and waste heat recovery by directly converting thermal energy into electricity. To harvest energy from curved surfaces, such as human skin, mechanical flexibility and novel structure are needed in a thermoelectric generator (TEG) to build a high-temperature gradient. Conjugated polymers have the potential to act as thermoelectric materials due to their electrical conductivity, accessibility, non-toxicity, and low thermal conductivity. Herein, we report available multiwalled carbon nanotubes (MWNTs) and polyaniline (PANi) composites as inexpensive thermoelectric materials. In-situ polymerization took advantage of the π- π stacking between PANi and MWNTs, and optimized their interface to reach a high power-factor and improved mechanical robustness. Additive manufacturing was conducted to obtain a gill-mimicking flexible substrate which formed the PANi/MWNTs hybrids in an out-of-plane manner. The simulated temperature distribution showed the better ability of the gill-structured generator to yield high-temperature differences over a flat design. Extraordinary bendability and durability were shown in 1000 bending tests. Our demonstration presented stable voltage generated by the TEG on hot water containers, hot car roofs, and human skins. Moreover, the TEG can power a sensing system that reveals biosignals, such as joint movement and respiration, with a strain sensor. This project sheds light on health monitoring, wearable electronics, Internet-of-things, and human-computer interaction.