A free-standing carbon foam for rechargeable Zn–air batteries

A freestanding carbon foam is prepared through pyrolysis of metal-organic framework (MOF) nanosheet-embedded melamine foam, showing a low oxygen reaction potential gap of 0.71 V as well as superior performance to its powdered counterpart-based Zn-air battery. Such a high performance is attributed to the derived 3D architecture holding more exposed active sites and faster mass transport pathways compared to conventional MOF-derived powder electrocatalysts.