The team led by professors Zhang Qian, Mao Jun, and Cao Feng from the College of Frontier Sciences at Harbin Institute of Technology (Shenzhen campus) has achieved a breakthrough in thermoelectric materials by developing an inorganic thermoelectric aerogel. Their findings, titled High-Performance n-Type Flexible Inorganic Thermoelectric Aerogel for Energy Harvesting, have been published in Science Advances and offer a novel approach to lightweight and self-powered technologies in wearable electronic devices.
Achieving a sustainable, lightweight, and efficient energy supply has become a central challenge for both academia and industry. Thermoelectric materials can convert thermal energy from the human body or the environment into electricity, offering advantages such as high stability, strong reliability, and the absence of moving parts. However, traditional inorganic thermoelectric materials are limited by their high density, insufficient flexibility, and poor wearing comfort.
To address these challenges, the team of professors Zhang, Mao, and Cao, in collaboration with Professor Li Mingyu's team from Shenzhen campus, proposed a stepwise synthesis strategy. Using silver (Ag) aerogel as a precursor and precisely controlling the selenization reaction, they successfully constructed an inorganic three-dimensional network thermoelectric aerogel based on silver selenide (Ag2Se) nanowires. This offers an innovative solution for self-powered wearable devices.
The research team fabricated silver selenide thermoelectric aerogels characterized by high porosity (95-99 percent) and ultra-low density (0.04-0.54 g cm^(-3)). The material demonstrates excellent thermoelectric performance, achieving a room-temperature figure of merit (zT) of 0.17, and a zT of 0.24 at 383 Kelvin (K). It also possesses superior thermal insulation capabilities, with a minimum thermal conductivity of only 0.03 Watt (W) m^(-1) K^(-1). The team also employed polyimide (PI) for encapsulation – coating the silver selenide surface with a nanoscale PI layer.
This study developed an inorganic thermoelectric aerogel that combines high thermoelectric performance with good mechanical flexibility, overcoming the field's long-standing reliance on organic or carbon-based materials. The proposed stepwise-synthesis strategy provides a universal method for designing other high-performance inorganic flexible thermoelectric materials. This work advances the development of thermoelectric materials toward ultra-lightweight and flexible applications and establishes a key material foundation and innovative concepts for frontier fields such as next-generation self-powered wearable electronics, soft robotics, and biomimetic skin.
HIT Shenzhen campus is the primary affiliation for this paper. Assistant Research Professor Wang Xiaodong is the first author, and Associate Professor Zhu Wenbo is the co-first author. Professors Zhang, Li, Mao, and Cao serve as co-corresponding authors. This research was supported by foundations including the National Natural Science Foundation of China.
Figure: Preparation and performance optimization of Ag2Se nanowire aerogels. (a) Schematic diagram of the preparation process for Ag2Se nanowire aerogels. (b) Photograph of the ultra-light Ag2Se nanowire aerogels. (c) SEM of the Ag2Se nanowire aerogels. Comparison with reported organic-based and carbon-based aerogel thermoelectric materials: (d) Bar chart of room-temperature zT values. (e) Relationship between the absolute value of the Seebeck coefficient (|S|) and room-temperature electrical conductivity (σ) for the Ag2Se nanowire aerogels. (f) Schematic of the Ag2SePI nanowire aerogel, the inset shows a transmission electron microscope image (scale bar: 50 nm).