Synergistically Enhancing Dispersibility and Thermoelectric Performance of Carbon Nanotubes by Biomass Carboxymethyl Cellulose

Single-walled carbon nanotubes (SWCNT) have unique potential in the fields of wearable devices and flexible thermoelectric (TE) materials. However, limited attention has been devoted to investigating the thermoelectric performance of CNT with natural cellulose. This study investigates the effects of carboxymethyl cellulose (CMC) with varying contents and degrees of substitution (DS) on the microstructure and thermoelectric performance of SWCNT. A significant interaction between the carboxylate groups and SWCNT leads to charge alterations within SWCNT, resulting in an elevated carrier concentration and improved dispersion of SWCNT. Consequently, when the CMC content was 20 wt % and the DS value was 0.7, the highest power factor of 336 μW m–1 K–2 was achieved, significantly surpassing that of pristine SWCNT. Moreover, the CMC/SWCNT film-based thermoelectric generator exhibits an output power of up to 284.7 nW under a temperature difference of 30 K and demonstrates stable temperature-sensing ability. This study paves the way for the development of high-performance TE materials for energy harvesting.