High-Power Formate/Dioxygen Biofuel Cell Based on Mediated Electron Transfer Type Bioelectrocatalysis

A high-power mediated electron transfer type formate (HCOO – )/dioxygen (O 2 ) biofuel cell is reported herein. The cell utilizes a Ketjen Black modified waterproof carbon cloth as the electrode material. The bioanode comprises tungsten-containing formate dehydrogenase and a viologen-functionalized polymer, whereas the biocathode comprises bilirubin oxidase and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate). In addition, a gas diffusion type system was employed for the biocathode to realize a high-speed O 2 supply. These electrodes exhibited a large current density of 20 mA cm –2 in the quiescent steady state for both HCOO – oxidation and O 2 reduction. Finally, these electrodes were coupled to construct an HCOO – /O 2 biofuel cell without a separator. The cell exhibited a maximum power density of 12 mW cm –2 at a cell voltage of 0.78 V under quiescent conditions and an open-circuit voltage of 1.2 V. We show the great potential of HCOO – for the fuel of biofuel cells.