Core-shell template derived porous 3D-Fe/Fe2O3@NSC composites as high performance catalysts for aqueous and solid-state rechargeable Zn-air batteries

•N, S co-doped 3D-carbon encapsulated Fe/Fe2O3 composite has been constructed.•The composite is built by template thermolysis transformation oxidation strategy.•The formation of interface is in favor of optimizing the electronic configuration.•The optimal 3D-Fe/Fe2O3@NSC-900 exhibits excellent performance with △E of 0.718V.•3D-Fe/Fe2O3@NSC-900 based aqueous and solid-state ZABs deliver impressive performances.