An approach to direct liquid fuel cells (DLFCs) has been investigated where the air cathode is replaced with a redox couple cathode. This different configuration, a direct liquid redox fuel cell (DLRFC), reduces the effect of fuel crossover, eliminates cathode flooding, allows the use of a carbon-based three-dimensional electrode for the cathode, and increases cell design flexibility. Furthermore, the use of a carbon-based cathode significantly reduces the fuel cell's total platinum group metal content. Contrary to conventional DLFCs, high fuel concentrations can be employed in this type of configuration without depolarizing the cathode because the carbon-based cathode is selective to the redox couple only. Cyclic voltammetry (CV), differential scanning calorimetry (DSC), conductivity measurements, and fuel cell tests were used to characterize the system. CV and DSC have confirmed the electrochemical stability of methanol and the redox couple (Fe2+/Fe3+) up to 70 degrees C and in the potential window of 0-1.2 V vs a standard hydrogen electrode. DLRFCs at 70 degrees C employing the Fe2+/Fe3+ redox couple at the cathode delivered peak power densities 5 and 3 times greater than DLFC equivalents (ambient pressure air) for acidic anolytes containing 16.7 M CH3OH and 18 M HCOOH, respectively. (C) 2008 The Electrochemical Society. [DOI: 10.1149/1.2993981] All rights reserved.