A liquid-electrolyte-free anion-exchange membrane direct formate-peroxide fuel cell

•An anion-exchange membrane direct formate-peroxide fuel cell was reported.•The theoretical cell voltage reaches as high as 1.92 V.•A half-hour constant-current discharge that almost remained unchanged was achieved.•Effect of formate concentrations on cell performance was investigated.

Conventionally, two critical issues that limit the steady-state discharge of alkaline liquid fuel cells are the pH-dependant problem at anode and the carbonation problem at cathode. The present work addresses these two issues by reporting an anion-exchange membrane direct liquid fuel cell that uses a pH-insensitive fuel, formate, as the reductant, and a CO2-free reactant, hydrogen peroxide, as the oxidant, referred to as anion-exchange membrane direct formate-peroxide fuel cell (AEM DFPFC). Theoretically, the cell voltage of the AEM DFPFC can be as high as 1.92 V. It has been experimentally demonstrated that a conceptual half-hour constant-current discharge of the AEM DFPFC almost remains unchanged, even eliminating the supporting electrolytes at both anode and cathode. In contrast, an anion-exchange membrane direct ethanol fuel cell (AEM DEFC) shows a sharp decline in constant discharge within a few seconds.