NOVELTY - Supported ceramic membrane (I) comprises: a first layer of a fugitive-containing ceramic electrolyte material in the green state; a layer of a dense ceramic electrolyte material in the green state positioned above the fugitive-containing layer; and a second layer of the fugitive-containing ceramic electrolyte material positioned above the dense ceramic electrolyte layer, where the tri-layer assembly is laminated and then sintered to form a composite structure, the fugitive-containing ceramic electrolyte layers becoming porous after sintering.    USE - (I) is useful to make electrochemical cell (claimed). (I) is useful in electrochemical separations or catalytic reactors e.g. solid oxide fuel cells and oxygen separation membranes.    ADVANTAGE - (I) is well suited for the subsequent infiltration of electrochemically active species or their precursors (e.g. solutions, slurries and salts) for the enhancement of chemical or electrical transport to the membrane as well as the application of current carrying layers. (I) reduces warpage during sintering and provides satisfactory gas flow to the membrane after infiltration.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) an electrochemical cell comprising: (I); an anode material deposited on an outer surface of (I); and a cathode material deposited on the opposing outer surface of (I);    (2) an electrochemical cell stack comprising: either a first dense electronically conductive plate such as nickel chrome superalloy or ferritic stainless steel, a first electrochemical cell having an outer surface secured to the first conductive plate, a second dense electronically conductive plate secured to the opposing outer surface of the first electrochemical cell, a second electrochemical cell having an outer surface secured to the opposing surface of the second conductive plate, and a third dense electronically conductive plate secured to the opposing outer surface of the second electrochemical cell; or a first dense electronically conductive ceramic plate, a first tri-layer assembly, a second dense electronically conductive ceramic plate adjacent to the second fugitive-containing layer of the tri-layer assembly, a second tri-layer assembly, and a third dense electronically conductive ceramic plate adjacent to the second fugitive-containing layer of the second tri-layer assembly, where the layered assembly is laminated and then sintered to form a composite structure, the fugitive-containing ceramic electrolyte layers becoming porous after sintering, an anode is applied to alternating porous layers formed after sintering and a cathode is applied to the remaining porous layers;    (3) a preparation of (I);    (4) the production of an electrochemical cell comprising: depositing an anode material on an outer surface of (I); and depositing a cathode material on the opposing outer surface of (I); and    (5) the production of an electrochemical cell stack comprising: either providing n electrochemical cells (where n is greater than or equal to 2), providing n+1 dense electronically conductive plates, securing each of n-1 plates between the anode surface of one of the n electrochemical cells and the cathode surface of another one of the n electrochemical cells, securing each of the remaining 2 plates to an outer surface of one of the outermost of the n electrochemical cells, and heating the layered assembly to the operating temperature of the electrochemical cells; or providing n tri-layer assemblies, providing n+1 dense electronically conductive ceramic plates; securing each of n-1 plates between the first layer of one of the n tri-layer assemblies and the second layer of one of the n tri-layer assemblies, securing each of the remaining 2 plates to an outer surface of one of the outermost of the n tri-layer assemblies, laminating and sintering the layered assembly to form a composite structure, the fugitive-containing ceramic electrolyte layers becoming porous after sintering, applying an anode material to alternating porous layers formed after sintering, and applying a cathode material to the remaining porous layers.