As alternative energy sources, such as solar, geothermal, wind, and wave, become viable in the future and cost-competitive with and environmentally favorable to conventional carbon-based energy sources, it will be increasingly important to develop low-cost energy-storage systems. These energy-storage systems may be either carbon-based or non-carbon-based but must possess a high energy-storage density, high operating efficiency, low cost, and ease of use, such as operation from the extensive electrical grid that exists throughout developed countries. Here, we present a novel energy-storage concept employing aqueous hydrogen peroxide (H2O2). The electrochemical synthesis of H2O2 from aerated water using a solid superacid cathodic electrode is proposed on the basis of a prior literature study and serves as the mechanism of stored energy. The subsequent generation of H-2 Plus O-2 (again via electrolysis on a cathodic superacid electrode) for use in a polymer electrolyte membrane (PEM) fuel cell is described and thus comprises energy release. For a 50 wt % aqueous H2O2 solution using a tungstated zirconia electrocatalyst with an energy-storage density of >0.49 MJ/kg solution and a full-cycle (synthesis to electrical energy output) operating efficiency of >35% has been estimated to be feasible based on prior literature work.