Metal-free, low-cost, and high-performance membraneless ethanol fuel cell

Renewable energy conversion from biomass in fuel cells can mitigate the imbalance between the carbon sequestration and sustainable energy demands. Ethanol biofuel cells based on NAD-dependent alcohol dehydrogenase (ADH)as catalyst are suitable alternatives; however, metal-free electrodes are still not effective for achieving a satisfactory power density. We report a membraneless and metal-free ethanol-O2 biofuel cell that is entirely composed of organic and biological molecules. The biofuel cell is based on a redox-active quinone-based catalyst produced by one-pot synthesis that operates efficiently with high power density (264 mW m?2), at mild conditions of pH and room temperature. The cost of this biofuel cell is more than 2.5-fold lower than that of a conventional system with a Pt-based electrocatalyst, potentially enabling cost-effective production of renewable electricity.