A self-assembled molecularly triboelectronegative cellulose nanofiber material with ultrahigh contact triboelectrification for the design of green triboelectric nanogenerators

The research and development of bio-based electronegative tribolayers will accelerate the further application of green triboelectric nanogenerators (G-TENGs), which is beneficial to alleviate the environmental pollution caused by the non-recyclability of traditional TENGs. Herein, we prepared a cellulose nanofiber (CNF) based triboelectronegative tribolayer material with ultrahigh triboelectric charge density, which is obtained by molecular self-assembly of 3-(triethoxysilyl) propionitrile (TESPN) on the surface of a CNF film. Due to the strong electron-withdrawing effect of cyano-groups, the modified CNF film tends to gain electrons and be negatively charged during the triboelectrification process. The results show that the CNF-TESPN@CNF-based green TENG can deliver a current of 14.4 mu A and a voltage of 251 V. Moreover, compared to electronegative cellulose acetate, the triboelectric charge density (TECD) of the modified CNF film was increased by 95%, showing ultrahigh contact electrification performance. The smart self-powered system can be used as a wearable device for an energy harvester or corrosion protection of metal surfaces in the ocean.