Bioinspired energy-free temperature gradient regulator for significant enhancement of thermoelectric conversion efficiency.

Enhancing thermoelectric conversion efficiency (TCE) is pivotal for advancing global energy conservation and emission reduction initiatives. Traditional approaches primarily focus on microscopic strategies such as bandgap engineering, chemical potential adjustments, and entropy engineering. However, these methods face substantial limitations in practical applications due to challenging material property requirements. Additionally, the efficiencies achieved remain modest, constrained by the interdependent nature of electrical and thermal conductivities, which typically vary concurrently. Inspired by the thermoregulation mechanisms in biological organisms, we propose here a macroscopic strategy based on an expanded-plane (EP) meta-structure. Such a meta-structure, of the thermal gradient regulator type, exploits the temperature gradient concentrating effect to significantly boost TCE. We prove, both numerically and experimentally, how the proposed device can achieve temperature gradient concentration under diverse conditions. Remarkably, under undistorted temperature background conditions, we measured an striking efficiency enhancement of [Formula: see text]. This work highlights the EP thermal gradient regulator's ability to boost thermoelectric efficiency, valuable across domains: aiding efficient chip cooling in microelectronics and powering wearable medical devices.