Nanostructured　air　electrodes　play　a　crucial　role　in　improving　the　electrocatalytic　activity　of　oxygen　reduction　and　evolution　reactions　in　solid　oxide　cells　(SOCs).　Herein,　we　report　the　fabrication　of　a　nanostructured　BaCoO3-decorated　cation-deficient　PrBa0.8Ca0.2Co2O5+δ　(PBCC)　air　electrode　via　a　combined　modification　and　direct　assembly　approach.　The　modification　approach　endows　the　dual-phase　air　electrode　with　a　large　surface　area　and　abundant　oxygen　vacancies.　An　intimate　air　electrode-electrolyte　interface　is　in　situ　constructed　with　the　formation　of　a　catalytically　active　Co3O4　bridging　layer　via　electrochemical　polarization.　The　corresponding　single　cell　exhibits　a　peak　power　density　of　2.08　W　cm-2,　an　electrolysis　current　density　of　1.36　A　cm-2　at　1.3　V,　and　a　good　operating　stability　at　750　°C　for　100　h.　This　study　provides　insights　into　the　rational　design　and　facile　utilization　of　an　active　and　stable　nanostructured　air　electrode　of　SOCs.　©　2023　American　Chemical　Society.