Fully wood-based green triboelectric nanogenerators

Highlights: • Fabrication of triboelectric nanogenerator using highly flexible and porous wood. • Output voltage can be tuned from 4.4 V to 90.1 V through surface functionalization. • Demonstration of bio-degradable TENG to solve the microplastic pollution problem. In recent times, triboelectric nanogenerators (TENGs) have been extensively studied as green sources for harvesting energy. Paradoxically, TENGs are mostly based on nondegradable synthetic plastics, which are the main source of marine pollution. Here, we explore the possibility of adopting alternative materials like natural wood-based TENGs to reduce marine microplastics. This is the first report on a TENG employing flexible porous wood-based friction layers as both negative and positive materials to enhance triboelectric output. The all-wood-based TENG device demonstrates a very high voltage of 90.1 V and current density of 114.4 nA·cm⁻², corresponding to a power of 54.53 mW on a 4.7 × 10⁶ Ω load at 8.2 N. The observed output voltage from the chemically-treated wood-based TENG can be increased to ~20.5 times compared to the delignified wood-based TENG. This work can provide a new mode for bio-degradable TENG systems to solve the escalating plastic waste problem.