Solid　oxide　electrolysis　cell　(SOEC)　can　perform　CO2　electrolysis　to　produce　CO　feedstock.　In　this　work,　we　show　Sr2Fe1.5+xMo0.5O6-δ　with　exsolved　Fe　nanoparticles　to　enhance　the　activity　to　CO2　electrolysis.　A　single　SOEC　with　a　configuration　of　SF1.5+xM-SDC/LSGM/LSM-SDC　shows　a　current　density　of　1.16　A　cm−2　at　1.8　V,　which　presents　the　CO　production　rate　of　6.85　mL　min−1　cm−2　and　the　current　efficiency　of　up　to　96.3%　at　850　°C.　We　further　demonstrate　a　stable　electrolysis　performance　without　obvious　degradation　being　observed　even　after　a　long-time　operation　of　100　h.　The　exsolved　metal-oxide　interfaces　function　as　three　phase　boundary　which　transports　gas　molecules,　oxygen　ions　and　electrons　and　therefore　accommodate　CO2　splitting　in　electrochemical　process.　©　2020　Hydrogen　Energy　Publications　LLC