An electrochemical cell array, comprising: an ion conducting composite layer that includes two or more electrically conductive components, each electrically conductive component having one or more electrically conductive passageways; one or more dielectric components, each dielectric component having one or more ion-conducting passageways; and one or more interface regions; wherein the electrically conductive components and the dielectric components are adjacently arranged to provide a fluidically impermeable composite layer; and wherein the interface regions are disposed between adjacent dielectric components and conductive components; and wherein the interface regions are made of an electrically non-conductive and ionically non-conductive dielectric material that bonds to both the dielectric components and the conductive components; one or more first coatings (106, 602, 606) in contact with the first side of the composite layer; and one or more second coatings (104, 604, 608) in contact with the second side of the composite layer; wherein each first coating is in contact with at least one of the ion-conducting passageways of a first dielectric component and in electrical contact with at least one of the electrically conductive passageways of a first electrically conductive component; and wherein each second coating is in contact with at least one of the ion-conducting passageways of a second dielectric component and in electrical contact with the at least one electrically conductive passageway of the first electrically conductive component, sufficient to provide an electrically conductive pathway from the first side of the composite layer to the second side of composite layer between adjacent electrochemical cells in the array; and wherein one or both of the first coating and the second coating are catalytically active; and wherein the electrically conductive components, the dielectric components, and the interface regions collectively define a substantially flat first surface and a substantially flat second surface; wherein each of the first coatings (602, 606) and the second coatings (604, 608) include an edge that is located over a width of one of the interface regions, the width sufficient to enable an electrical discontinuity to be formed between coatings of adjacent electrochemical cells. an ion conducting composite layer that includes two or more electrically conductive components, each electrically conductive component having one or more electrically conductive passageways; one or more dielectric components, each dielectric component having one or more ion-conducting passageways; and one or more interface regions; wherein the electrically conductive components and the dielectric components are adjacently arranged to provide a fluidically impermeable composite layer; and wherein the interface regions are disposed between adjacent dielectric components and conductive components; and wherein the interface regions are made of an electrically non-conductive and ionically non-conductive dielectric material that bonds to both the dielectric components and the conductive components; one or more first coatings (106, 602, 606) in contact with the first side of the composite layer; and one or more second coatings (104, 604, 608) in contact with the second side of the composite layer; wherein each first coating is in contact with at least one of the ion-conducting passageways of a first dielectric component and in electrical contact with at least one of the electrically conductive passageways of a first electrically conductive component; and wherein each second coating is in contact with at least one of the ion-conducting passageways of a second dielectric component and in electrical contact with the at least one electrically conductive passageway of the first electrically conductive component, sufficient to provide an electrically conductive pathway from the first side of the composite layer to the second side of composite layer between adjacent electrochemical cells in the array; and wherein one or both of the first coating and the second coating are catalytically active; and wherein the electrically conductive components, the dielectric components, and the interface regions collectively define a substantially flat first surface and a substantially flat second surface; wherein each of the first coatings (602, 606) and the second coatings (604, 608) include an edge that is located over a width of one of the interface regions, the width sufficient to enable an electrical discontinuity to be formed between coatings of adjacent electrochemical cells.