Enzymeless multi-sugar fuel cells with high power output based on 3D graphene-Co₃O₄ hybrid electrodes

Biofuel cells (BFCs), which use enzymes as catalysts to harvest energy from green and sustainable fuels abundantly producible from biological systems, are promising next-generation energy devices. However, the poor stability and high specificity to only one fuel type of these bio-catalysts largely limits the practical use of current BFCs. In this contribution, we demonstrate a unique fuel cell which, equipped with two identical enzyme-free electrodes based on Co₃O₄ coated 3D graphene, is able to efficiently harvest electricity from various sweet biofuels (glucose, sucrose, or lactose). Taking advantage of the dual catalytic ability of nanostructured Co₃O ₄ for both glucose oxidation and oxygen reduction as well as the exceptional electrical and structural properties of 3D graphene, our glucose-powered fuel cell, with good long-term stability, offers high open circuit voltage (∼1.1 V) and power density output (2.38 ± 0.17 mW cm^-2).