Flexible films of tourmaline thermoelectric composite via acid treatment and embedding single-walled carbon nanotubes

Tourmaline (TM) belongs to a precious mineral resource with versatile functions like piezoelectricity and negative ion release capability. However, the report on their thermoelectric (TE) performance is scarce, possibly owing to their intrinsic powder state and low electrical conductivity. Herein, flexible films of TM-based TE composites are prepared by embedding single-walled carbon nanotubes (SWCNTs). Using acid-treatment of TMs (a-TM), the a-TM/SWCNT composites display the maximum power factor of 335.3 ± 36.6 μW m−1 K−2 at room temperature, due to effective removal of impurities in TMs and enhanced charge transfer between a-TM and SWCNTs. This work provides a convenient method to address the flexible films of TE materials and demonstrates the high potential of TMs in flexible TE applications.