High-output current density of the triboelectric nanogenerator made from recycling rice husks

Highlights: • The first demonstration of triboelectric nanogenerator using recycling rice husks. • The current density reaches 5.7 mAm^-2 based on dielectric-to-dielectric TENG. • The Si-OH bonds in the RH_SiO2 film exhibit a strong tendency of repulsing electron. This work, we are the first to discover the high-output current density of the triboelectric nanogenerator (TENG) using rice husks as a source material. The raw rice husks (RH) can be directly phase transited into the amorphous SiO₂ (RH_SiO2) structure with highly nanoporous fragments by the thermal annealing with additional acid hydrolysis process. The RH_SiO2-TENG׳s configuration is designed by polytetrafluoroethene (PTFE) and RH_SiO2 films, which are chemically and thermally more stable than the metallic film. The pore size around 20–40 nm is widely distributed throughout the SiO₂ fragments that possess rich Si–O–Si and OH stretching bonds with strong tendency of repulsing electron because the H atoms have an extremely low electron affinity, leading to the RH_SiO2 film exhibits much lower electron affinity when compared with the commercial SiO₂ nanoparticles. As a consequence, the area power density of the RH_SiO2 triboelectric nanogenerator (RH_SiO2-TENG) reaches 0.84 W m⁻² with a peak short-circuit current density of 5.7 mA m⁻². Such a short-circuit current density is almost among the highest reported value based on dielectric-to-dielectric mode triboelectric nanogenerators. Rice husk possess many advantageous traits such as their light weight, low cost, being environmentally friendly, high porosity, excellent robustness, exceptionally chemical and thermal stability for superior corrosion resistance, makes it a valuable material for industrial applications.