For the first time fully bio-derived thermosets have been synthesized from abundantly available, low cost, renewable feedstocks through a simple, solvent-free and catalytic process for the fabrication of triboelectric nanogenerators...

A biobased thermosetting polyamide has been synthesized through the crosslinking of epoxidized soybean oil (ESO) with hexamethylenediamine (HMDA) for application in sustainable energy harvesting devices, triboelectric nanogenerators (TENGs). A simple synthetic method requiring neither a solvent nor catalysts was employed. Amide formation was confirmed by FTIR signals corresponding to CO stretching at ∼1650 cm–1, N–H bending vibration at ∼1540 cm–1, and C–N stretching at 1168 cm–1. Polyamides of ESO/HMDA demonstrated excellent thermal stability (displaying a DTG peak at around 460 °C), high hydrophobicity with a water uptake of lower than 1.5%, and contact angles in the range of 86–120°. Importantly, the ESO/HMDA TENG exhibited outstanding electrical performance compared to other biobased devices, with the highest output voltage and current of 150 V and 14 μA, respectively. The high efficiency of the TENG was attributed to the significant nitrogen content within the polyamide structure, where enhanced electrical performance correlated with greater ratios of HMDA. ESO/HMDA biobased polyamides offer an exciting new opportunity for utilization in the fabrication of sustainable energy harvesting devices, such as TENGs.

A strategy to enhance the energy conversion performance of a cement-based triboelectric nanogenerator (TENG) has been proposed for large-scale energy harvesting from human footsteps. A cement-carbon black (CB) composite is fabricated by incorporating CB nanoparticles with a hydroxyethyl cellulose (HEC) admixture and used as a triboelectric material for TENG. The fabricated cement-CB@HEC TENG exhibits a 13fold enhancement of the electrical output with the highest power density of 2.38 W/m 2 . The tremendous improvement is ascribed to a good dispersion of conductive CB nanoparticles in the cement matrix, which is key for achieving a high dielectric constant that is required to intensify the triboelectric charge density of TENG. Moreover, it was found that the addition of the HEC admixture plays a crucial role in not only providing a good dispersion of CB for generating dielectric polarization but also facilitating the development of a microstructure and crystallization of cement hydration products to reduce the formation of air voids and micropores. These factors synergistically contribute to the improved dielectric constant and compressive strength of the cement-CB@HEC composite. This remarkable strategy presents great prospects for the development of smart cement materials for realizing applications in large-scale energy harvesting toward sustainable, clean, and renewable energy sources.

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