the invention concerns an oxide ion conductive ceramic membrane , characterized in that it comprises a non - null finite volume with non - null total thickness e , comprising a dense layer of a solid electrolyte , a so - called bonding layer , of two porous electrodes and , two porous current collectors and , and at least at least a coating porous layer , characterized in that the thickness e of the volume of said membrane , is equal to the sum of the thickness of each of said elements . the membrane is used for separating oxygen from air or from a gas mixture containing same .