Wood-inspired high strength and lightweight aerogel based on carbon nanotube and nanocellulose fiber for heat collection

Wood is one of the most abundant materials in nature, with excellent mechanical properties and anisotropy. Its main component, cellulose has excellent dispersion properties and biocompatibility after nano-treatment, which has aroused the interest of researchers. Therefore, this study prepared a thermoelectric aerogel based on carboxylated nanocellulose fiber and carbon nanotube, and made it have a wood-like anisotropic structure through directional freezing technology. The aerogel exhibited excellent mechanical properties and had the stress of up to 152 kPa when compressed at 90%. It also exhibited low thermal conductivity (0.03-0.08 W/mK) and density (7.5 mg/cm3). When the device was at a temperature difference of 30 K, the single output power was 0.23 nW. This work confirmed the dispersion effect of carboxylated nanocellulose fiber on carbon nanotube, and the enhancement of the wood-like structure on thermoelectric generators. It provided new ideas and solutions for the construction of thermoelectric devices.