Metal/bacteria cellulose nanofiber bilayer membranes for high-performance hydrovoltaic electric power generation

Hydrovoltaic devices that produce electricity from water represent a promising solution for green energy harvesting. Hydrovoltaic power generators based on various emerging nanostructured materials have shown great potential in water-enabled electricity generation. However, the development of high-performance and practical hydrovoltaic devices remains limited because of low electric power generation, high cost of precursor materials, and complicated fabrication processes. In this study, we developed a novel metal-coated bacteria cellulose nanofiber bilayer membrane (MBCBM) for high-performance hydrovoltaic power-generation devices. The top side of the MBCBM has metal-bacteria cellulose (BC) nanofibers that serve as a conducting electrode for fast charge carrier collection, whereas the bottom side has BC nanofibers that serve as hydrovoltaic materials for high efficient energy generation. A Schottky barrier was incorporated into the hydrovoltaic device, which enhanced the electric power output. Experiments revealed that the optimized single-MBCBM based hydrovoltaic device generated a maximum voltage of 0.935 V, current of 7.51 mA, and power output of 6.07 mW with a 50 μl electrolyte solution. The hybrid membrane and device design concept is expected to effectively utilize practical sustainable and clean energy sources for Internet of Things (IoT) devices and self-powered wearable devices in next-generation electronics.