Sustainable high-performance density—nanoporous composite wood for water evaporation-induced electricity generation

• An electricity nanogenerator with high power and current densities is fabricated. • Effects of reduced graphene oxide ratio and wood thickness are examined. • The power output is improved by high charge transfer and surface ion density. • An outstanding power density of 310 nW cm −2 is obtained experimentally. Water evaporation-induced electricity generation, an emerging renewable energy-harvesting technology, directly captures electricity from water evaporation by utilizing the interaction between material surfaces and water molecules. Water evaporation-induced electricity generator (WEIG) offers a distinct advantage in mitigating the limitations of conventional renewable power sources, such as intermittency, geographical constraints, and climate dependence. Yet, its potential is limited by the low power output stemming from insufficient charge mobility and the solid-water interfacial interaction. Herein, a facile and efficient WEIG based on two-dimensional nanoporous polypyrrole-reduced graphene oxide nanocomposite coated wood is demonstrated for green electricity generation. The device can generate continuous electric power with a maximum output power density of 310 nW cm −2 and a current density of 8.77 µA cm −2 , surpassing the performance of prior wood-based WEIGs. The superior performance is attributed to the intrinsic properties of the composite structure being nanoporous with high electrical conductivity, high zeta potential, and hydrophilicity. The findings of the present study not only promote the development of WEIGs but also encourage the application of sustainable and eco-friendly materials in future green electricity generation systems.