Chinese researchers develop high-efficiency flexible thermoelectric material for wearables

BEIJING -- Chinese researchers have developed a highly efficient, flexible thin-film material for power generation, representing a major breakthrough in flexible power technology for smart wearables, the Science and Technology Daily has reported.

While wearable devices such as smartwatches and fitness trackers are advancing rapidly, their reliance on batteries -- which necessitates frequent replacements or charging -- remains a barrier to wider adoption.

Thermoelectric technology, which converts body heat directly into electricity, presents an ideal solution due to its safety, eco-friendliness and lack of mechanical components. However, current flexible thermoelectric materials demonstrate low performance, and most power-generating devices use planar structures that fail to produce adequate electricity for electronic devices.

The research team from the Institute of Electrical Engineering under the Chinese Academy of Sciences employed a chemical solution method to synthesize fine silver selenide (Ag₂Se) nanowires. These were combined with graphene and applied to a porous nylon substrate.

Using filtration and rapid hot-pressing techniques, the team produced an ultra-high-performance flexible power-generating film. Its innovative structure delivers the highest power density ever reported for flexible thermoelectric devices using silver selenide.

The team then constructed a three-dimensional miniature arch bridge-shaped generator incorporating 100 paired thermoelectric units made from this film.

This arched structure makes better use of the temperature differential between human body and environment. The resulting body heat generator achieves world-record for power output for its class -- sufficient to operate small devices like electronic watches and hygrothermographs.

This study successfully applies thermoelectric conversion technology to flexible power-generating devices, offering an efficient and sustainable energy solution for smart wearables, said Ding Fazhu, a researcher at the institute.

The research findings were published in the journal Nature Communications.