Intrinsically stretchable thermoelectric materials for highly efficient thermal energy conversion

Abstract

Abstract Diversification of heat sources with intense deformation and dynamic changes presents mechanically harsh environments for thermal energy regulation, urging thermoelectric (TE) materials to simultaneously achieve intrinsic stretchability and high TE figure of merit (zT). Nevertheless, the evident trade-off between the two has circumscribed adopting conventional TE materials and technology for mechanically sustainable framework, thereby necessitating fundamental material-oriented breakthroughs. Herein, we develop restructured carbon nanotubes that flawlessly accommodate extreme deformation while harvesting heat with high efficiency. Restructuring the nanotube network with polymeric dopants and ionic liquid can independently promote electrical conductivity by hole-doping and regulating inter-nanotube connectivity. The established nanotube-polymer heterointerfaces instigate phonon scattering to suppress thermal conductivitry and facilitate TE efficiency (zT ≥10-1). Concurrently, such restructuring allocates greater free volume to the network and alleviates nanotube aggregation, thereby imparting extreme intrinsic stretchability (≥180%) with minimal compromise in TE performance. To demonstrate the outstanding advances enabled by such unprecedented pair of exceptional material stretchability and improved energy conversion efficiency, we showcase practical thermal energy regulation applications encompassing stretchable thermoelectric generators and Peltier-induced temperature regulation.