Abstract: This invention describes a novel DBFC employing hydrogen peroxide as oxidant with a power density of about 350 mW/cm2 at the cell voltage of almost 1.2V at 70° C.; the open-circuit voltage of the DBFC being as high as about 2V, the use of liquid reactants in DBFCs not only simplifies the engineering problems at the front end of the fuel cell driving down complexity and hence cost but operating a DBFC with an oxidant such as hydrogen peroxide also extends the operational domain of fuel cells to locations where free convection of air is limited, e.g. under water applications.