Vertically aligned cellulose nanofiber/carbon nanotube aerogel-infused epoxy nanocomposites for highly efficient solar-thermal-electric conversion

Solar-driven thermo-electric generation (STEG) emerges as a promising solution to mitigate the global energy shortage. However, the practical application of conventional photothermal materials equipped with STEG is limited due to low solar thermal conversion efficiency. Herein, we fabricated an epoxy resin (EP) nanocomposite, EP/CCA80, with excellent photo-thermal-electric conversion properties by embedding a vertically aligned aerogel consisting of cellulose nanofibers (CNF) and carboxylated multi-walled carbon nanotubes (CMWCNTs) into a transparent EP matrix. EP/CCA80 composites possessed a broad light absorption range from 200 nm to 2500 nm and excellent photothermal properties. Under illumination of 1.0 kW m–2, EP/CCA80 achieved a notable stable temperature of 93.2°C and a photothermal conversion efficiency of up to 54.35% with only 0.65 wt% CMWCNTs inclusion. Additionally, coupled with thermoelectric (TE) devices, the EP/CCA80 composite facilitated a significant temperature difference and voltage output of up to 25.3°C and 160.29 mV (1.0 kW m–2), respectively, which could power a small fan to rotate at a speed of 193 min–1. Such materials are poised to offer viable solutions for enhancing energy accessibility in remote regions, thereby contributing to the reduction of energy shortages and environmental degradation.