Bacterial cellulose/reduced graphene oxide bilayer films for moist-electric power generation

Abstract

Moist-electric generatoris an emerging energy harvesting technology that converts the energy reserved in the ubiquitous atmospheric moisture into electricity. However, existing moist-electric generators (MEGs) as a direct power supply for practical applications remain challenging due to instantaneous and low electrical output, intricate procedures, and high energy-consuming materials. Therefore, there is an urgent requirement for MEGs with high efficiency and continuous power generation performance. This work reports an environmentally friendly bacterial cellulose (BC)/reduced graphene oxide (RGO) bilayer film (B–BRG bf) with a heterogeneous structure prepared by a facile vacuum filtration method, which consists of different contents of oxygen-containing functional groups between the top and bottom layers to maintain moisture differences. A centimeter-sized B–BRG bf-based MEG can generate a maximum output power density of 3.06 μW cm⁻², an extreme voltage of 1.08 V, and a current of 53.80 μA at RH = 90%. Additionally, B–BRG bf MEG demonstrates all-weather adaptation, delivering a maximum voltage output of 1.20 V for up to 125 h in an outdoor environment (T = 19–51 °C, RH = 28–94%), which exceeds most cellulose-based MEGs with continuous output capability. This work provides fresh insights into the design of high-performance MEGs for self-powered applications.