Highly efficient unitized regenerative hydrogen peroxide cycle cell with ultralow overpotential for renewable energy storage

The potential large-scale applications of intermittent renewable energy sources require inexpensive, efficient, and less-resource-demanding storage systems to achieve grid balancing. Conventional unitized regenerative fuel cells (URFCs) based on the H2–H2O cycle are promising but suffer from high overpotential low efficiency. Here we demonstrate a highly efficient hydrogen peroxide cell (UR-HPCC) for storage. prototype utilizes carbon-based platinum group metal-free catalyst containing atomically dispersed Co N dopants (Co–N–C) as bifunctional oxygen electrode oxidation reaction (HPOR) two-electron reduction (2e-ORR) in H2O2 electrolyzer modes, respectively. Further, this exhibits close-to-zero with remarkably round-trip efficiency over 90%, which is attributed ideal catalytic properties Co–N–C toward HPOR 2e-ORR. thermodynamic analysis these single-intermediate reactions indicates intrinsic superiority UR-HPCC reversibility conventional URFCs, thus facilitating development future sustainable distributed generation systems.