Covalent organic frameworks derived hollow structured N-doped noble carbon for asymmetric-electrolyte Zn-air battery

We report a relatively low-temperature molten salt strategy to prepare hollow structured N-doped noble carbon (h-NNC) with highly desirable features of ultra-large surface area (1957 m2 g−1) and high graphitization, endowing the h-NNC with high activity toward catalysis of oxygen reduction reaction in acidic medium. The h-NNC is applied as cathode catalyst of an asymmetrical-electrolyte Zn-air battery, which exhibits an open circuit voltage of 2.11 V, a power density up to 270 mW cm−2, and an energy density of 1279 W h kg−1, behaving advantages over the conventional Zn-air batteries.