A Bi2Te3-Filled Nickel Foam Film with Exceptional Flexibility and Thermoelectric Performance

The past decades have witnessed surging demand for wearable electronics, for which thermoelectrics (TEs) are considered a promising self-charging technology, as they are capable of converting skin heat into electricity directly. Bi2Te3 is the most-used TE material at room temperature, due to a high zT of similar to 1. However, it is different to integrate Bi2Te3 for wearable TEs owing to its intrinsic rigidity. Bi2Te3 could be flexible when made thin enough, but this implies a small electrical and thermal load, thus severely restricting the power output. Herein, we developed a Bi2Te3/nickel foam (NiFoam) composite film through solvothermal deposition of Bi2Te3 nanoplates into porous NiFoam. Due to the mesh structure and ductility of Ni Foam, the film, with a thickness of 160 p.m, exhibited a high figure of merit for flexibility, 0.016, connoting higher output. Moreover, the film also revealed a high tensile strength of 12.7 +/- 0.04 MPa and a maximum elongation rate of 28.8%. In addition, due to the film's high electrical conductivity and enhanced Seebeck coefficient, an outstanding power factor of 850 mu W m(-1) K-2 was achieved, which is among the highest ever reported. A module fabricated with five such n-type legs integrated electrically in series and thermally in parallel showed an output power of 22.8 nW at a temperature gap of 30 K. This work offered a cost-effective avenue for making highly flexible TE films for power supply of wearable electronics by intercalating TE nanoplates into porous and meshed-structure materials.

Automated summary

There is a growing demand for wearable electronics and thermoelectric materials are considered a promising self-charging technology. This study developed a flexible and efficient composite film by depositing Bi2Te3 nanoplates into porous nickel foam. The film exhibited high tensile strength, flexibility, electrical conductivity, and Seebeck coefficient, resulting in a high power factor. A module fabricated with this film demonstrated a promising output power. This work provides a cost-effective approach for making highly flexible thermoelectric films for power supply in wearable electronics.