Stretchable Thermoelectric Fibers with Three-Dimensional Interconnected Porous Network for Low-Grade Body Heat Energy Harvesting
Jiahui Li, Bailu Xia, Xiao Xiao, Zhangfan Huang, Junyi Yin, Yawei Jiang, Shaolei Wang, Haiqi Gao, Qiuwei Shi, Yannan Xie, Jun Chen
Abstract
Electricity generation from body heat has garnered significant interest as a sustainable power source for wearable bioelectronics. In this work, we report stretchable n-type thermoelectric fibers based on the hybrid of Ti 3 C 2 T x MXene nanoflakes and polyurethane (MP) through a wet-spinning process. The proposed fibers are designed with a 3D interconnected porous network to achieve satisfactory electrical conductivity (σ), thermal conductivity (κ), and stretchability simultaneously. We systematically optimize the thermoelectric and mechanical traits of the MP fibers and the MP-60 (with 60 wt % MXene content) exhibits a high σ of 1.25 × 10 3 S m –1, an n-type Seebeck coefficient of −8.3 μV K –1, and a notably low κ of 0.19 W m –1 K –1 . Additionally, the MP-60 fibers possess great stretchability and mechanical strength with a tensile strain of 434% and a breaking stress of 11.8 MPa. Toward practical application, a textile thermoelectric generator is constructed based on the MP-60 fibers and achieves a voltage of 3.6 mV with a temperature gradient between the body skin and ambient environment, highlighting the enormous potential of low-grade body heat energy harvesting.