NOVELTY - Solid-oxide fuel cell (10) comprises: an electrolyte (16); an anode (12) electrically coupled to a first surface of the electrolyte; and a cathode electrically coupled to a second surface of the electrolyte. The cathode comprises a porous mixed ionic-electronic conductor having a porosity of 20-70% and pores. The cathode comprises an oxygen-reducing catalyst coating comprising an oxygen-reducing catalyst. The porous mixed ionic-electronic conductor comprises a perovskite compound.    USE - The solid oxide fuel cell is useful as auxiliary power units in vehicles to stationary power generation units.    ADVANTAGE - The cathode including a porous backbone of high ionic and electronic conductivity material infiltrated with a thin coating of catalysts has high stability and catalytic activity toward oxygen reduction and the cell exhibits improved cell performance and stability.    DETAILED DESCRIPTION - Solid-oxide fuel cell (10) comprises: an electrolyte (16); an anode (12) electrically coupled to a first surface of the electrolyte; and a cathode electrically coupled to a second surface of the electrolyte. The cathode comprises a porous mixed ionic-electronic conductor having a porosity of 20-70% and pores. The cathode comprises an oxygen-reducing catalyst coating comprising an oxygen-reducing catalyst. The porous mixed ionic-electronic conductor comprises a perovskite compound of formula (La1-xAxB1-yB2y). The oxygen-reducing catalyst is lanthanum strontium manganite, strontium-doped samarium cobaltite, calcium doped lanthanum cerate, calcium-doped lanthanum zirconate, gadolinium-doped ceria or samaria-doped ceria (18). The oxygen-reducing catalyst coating has a thickness of one monolayer to 30 nm and Some portion of the pores in the porous mixed ionic-electronic conductor has a pore surface where the oxygen-reducing catalyst coating is directly on the pore surface.    A = Sr at the A-site of the perovskite;    B1 = Co at the B-site of the perovskite;    B2 = Fe at the B-site of the perovskite; and    x, y = 0 to less than 1.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-section of the solid-oxide fuel cell.    Fuel cell (10)    Anode substrate (12)    Active anode interlayer (14)    Electrolyte (16)    Samaria-doped ceria barrier layer. (18)