Two approaches pertaining to the direct liquid redox fuel cell (DLRFC) have been investigated and demonstrated: mixed-reactant operation and in situ regeneration of the redox couple. The former involves supplying a mixed methanol Fe2+/Fe3+ redox electrolyte to the selective carbon cathode of the DLRFC and supplying the fuel to the anode via methanol crossover. This approach has the potential to significantly improve the cost, compactness, and volumetric and gravimetric power densities of the cell. The latter in situ regeneration approach involves substituting the fuel supply with air to spontaneously reverse the direction of electron flow in a DLRFC, which eliminates the need for an auxiliary regeneration unit and reduces the overall cost and complexity of a DLRFC system. Both modes of DLRFC operation, discharge, and regeneration, produce power that is unique compared to conventional systems.
Journal of The Electrochemical Society157, no. 4: B529–B535.