Robust, Flexible Thermoelectric Film for Energy Harvesting by a Simple and Eco-Friendly Method

As for the self-supporting composite films, it is significant to develop a structural design that allows for excellent flexibility while reducing the negative effect on thermoelectric (TE) properties. Herein, a robust, flexible TE film was fabricated by in situ chemical transformation and vacuum-assisted filtration without any organic solvents involved. The performance of the films was further optimized by adjusting the Ag/Te ratio and post-treatment methods. Owing to the semi-interpenetrating nanonetwork structure formed by AgxTe nanowires and bacterial cellulose, the obtained TE film displayed a high tensile strength of -,78.4 MPa and a high power factor of 48.9 mu W m-1 K-2 at room temperature. A slight electrical conductivity decrement of the TE film in flexible test (-,2% after 1000 bending cycles) indicates an excellent flexibility. Finally, a TE bracelet was assembled to harvest body heat energy, and a steady current of -,2.7 mu A was generated when worn on the wrist indoors. This work provides a reference for the structural design and practical application of flexible TE films.

Automated summary

In this study, a robust and flexible thermoelectric film was fabricated by in situ chemical transformation and vacuum-assisted filtration. The film exhibited high tensile strength and power factor, and excellent flexibility in flexible test.