NOVELTY - The method of operating a direct-fuel redox fuel cell (1), comprises supplying a catholyte to a platinum group metal (PGM)-free cathode of the fuel cell, supplying an electroactive organic fuel to an anode (12) of the fuel cell, and regenerating a reduced redox couple using a chemical regenerator comprising active carbon catalyst. The catholyte and cathode (18) includes a redox couple. The catholyte is discharged from the cathode without regeneration of the redox couple, and comprises an aqueous redox couple catholyte solution.    USE - The method is useful for operating a direct-fuel redox fuel cell.    ADVANTAGE - The method is capable of effectively operating the direct-fuel redox fuel cell using a range of fuel concentrations thus avoiding the significant cross-over of fuel, the cathode depolarization and the micro-organisms to harm microbial redox couple regenerators and thus improving mass transfer and reaction rate kinetics at the anode without introducing additional complications.    DETAILED DESCRIPTION - The method of operating a direct-fuel redox fuel cell (1), comprises supplying a catholyte to a platinum group metal (PGM)-free cathode of the fuel cell, supplying an electroactive organic fuel to an anode (12) of the fuel cell, and regenerating a reduced redox couple using a chemical regenerator comprising active carbon catalyst. The catholyte and cathode (18) includes a redox couple. The catholyte is discharged from the cathode without regeneration of the redox couple, and comprises an aqueous redox couple catholyte solution. The electroactive organic fuel is supplied to an anode at a concentration of 2 M to a maximum stoichiometric concentration of the fuel, 4 M to a maximum stoichiometric concentration of the fuel, 6 M to a maximum stoichiometric concentration of the fuel or 8 M to a maximum stoichiometric concentration of the fuel such that the concentration does not result in fuel cross-over that has more than a 10% negative effect on voltage or a 24 mV voltage loss at any given current density and a maximum stoichiometric concentration of the fuel.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a liquid fuel fed direct methanol redox fuel cell.    Direct methanol redox fuel cell (1)    Anode assembly (10)    Anode (12)    Anolyte flow field (14)    Cathode assembly (16)    Cathode. (18)