Patent Publication Number: US-8974981-B2

Title: Fuel cell system with interconnect

Description:
GOVERNMENT RIGHTS 
     This invention was made with U.S. Government support under Contract No. DE-FE0000303 awarded by the Department of Energy. The Government has certain rights in this invention. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to fuel cells and, in particular, to an interconnect for a fuel cell. 
     BACKGROUND 
     Fuel cells, fuel cell systems and interconnects for fuel cells and fuel cell systems remain an area of interest. Some existing systems have various shortcomings, drawbacks, and disadvantages relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology. 
     SUMMARY 
     The present invention includes a fuel cell system having an interconnect that reduces or eliminates diffusion (leakage) of fuel and oxidant by providing an increased diffusion distance and reduced diffusion flow area. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
         FIG. 1  schematically depicts some aspects of a non-limiting example of a fuel cell system in accordance with an embodiment of the present invention. 
         FIG. 2  schematically depicts some aspects of a non-limiting example of a cross section of a fuel cell system in accordance with an embodiment of the present invention. 
         FIG. 3  is an enlarged cross sectional view of a portion of the interconnect of  FIG. 2 . 
         FIGS. 4A and 4B  depict some alternate embodiments of interconnect configurations. 
         FIG. 5  depicts a hypothetical interconnect that is contrasted herein with embodiments of the present invention. 
         FIGS. 6A and 6B  show a top view and a side view, respectively, of some aspects of a non-limiting example of yet another embodiment of an interconnect. 
         FIG. 7  schematically depicts some aspects of a non-limiting example of a cross section of a fuel cell system having a ceramic seal in accordance with an embodiment of the present invention. 
         FIG. 8  schematically depicts some aspects of a non-limiting example of a cross section of another embodiment of a fuel cell system having a ceramic seal. 
         FIG. 9  schematically depicts some aspects of a non-limiting example of a cross section of yet another embodiment of a fuel cell system having a ceramic seal. 
         FIG. 10  schematically depicts some aspects of a non-limiting example of a cross section of an embodiment of the present invention having a chemical barrier. 
         FIG. 11  schematically depicts some aspects of a non-limiting example of a cross section of an embodiment of the present invention having a chemical barrier. 
         FIG. 12  schematically depicts some aspects of a non-limiting example of a cross section of an embodiment of the present invention having a chemical barrier and a ceramic seal. 
         FIG. 13  schematically depicts some aspects of a non-limiting example of a cross section of an embodiment of the present invention having a chemical barrier and a ceramic seal. 
         FIG. 14  schematically depicts some aspects of a non-limiting example of a cross section of an embodiment of the present invention having a chemical barrier. 
         FIG. 15  schematically depicts some aspects of a non-limiting example of a cross section of an embodiment of the present invention having a chemical barrier. 
         FIG. 16  schematically depicts some aspects of a non-limiting example of a cross section of an embodiment of the present invention having a chemical barrier, a ceramic seal, and a gap between a cathode conductor film and an electrolyte layer. 
         FIG. 17  schematically depicts some aspects of a non-limiting example of a cross section of an embodiment of the present invention having a chemical barrier, a ceramic seal, and a gap between an interconnect auxiliary conductor and an electrolyte layer. 
         FIG. 18  schematically depicts some aspects of a non-limiting example of a cross section of an embodiment of the present invention having a chemical barrier, a ceramic seal, and an insulator between a cathode conductor film and an electrolyte layer. 
         FIG. 19  schematically depicts some aspects of a non-limiting example of a cross section of an embodiment of the present invention having a chemical barrier, a ceramic seal, and an insulator between an interconnect auxiliary conductor and an electrolyte layer. 
     
    
    
     DETAILED DESCRIPTION 
     For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nonetheless be understood that no limitation of the scope of the invention is intended by the illustration and description of certain embodiments of the invention. In addition, any alterations and/or modifications of the illustrated and/or described embodiment(s) are contemplated as being within the scope of the present invention. Further, any other applications of the principles of the invention, as illustrated and/or described herein, as would normally occur to one skilled in the art to which the invention pertains, are contemplated as being within the scope of the present invention. 
     Referring to the drawings, and in particular  FIG. 1 , some aspects of a non-limiting example of a fuel cell system  10  in accordance with an embodiment of the present invention is schematically depicted. In the embodiment of  FIG. 1 , various features, components and interrelationships therebetween of aspects of an embodiment of the present invention are depicted. However, the present invention is not limited to the particular embodiment of  FIG. 1  and the components, features and interrelationships therebetween as are illustrated in  FIG. 1  and described herein. 
     The present embodiment of fuel cell system  10  includes a plurality of electrochemical cells  12 , i.e., individual fuel cells, formed on a substrate  14 . Electrochemical cells  12  are coupled together in series by interconnects  16 . Fuel cell system  10  is a segmented-in-series arrangement deposited on a flat porous ceramic tube, although it will be understood that the present invention is equally applicable to segmented-in-series arrangements on other substrates, such on a circular porous ceramic tube. In various embodiments, fuel cell system  10  may be an integrated planar fuel cell system or a tubular fuel cell system. 
     Each electrochemical cell  12  of the present embodiment has an oxidant side  18  and a fuel side  20 . The oxidant is typically air, but could also be pure oxygen (O 2 ) or other oxidants, e.g., including dilute air for fuel cell systems having air recycle loops, and is supplied to electrochemical cells  12  from oxidant side  18 . Substrate  14  of the present embodiment is porous, e.g., a porous ceramic material which is stable at fuel cell operation conditions and chemically compatible with other fuel cell materials. In other embodiments, substrate  14  may be a surface-modified material, e.g., a porous ceramic material having a coating or other surface modification, e.g., configured to prevent or reduce interaction between electrochemical cell  12  layers and substrate  14 . A fuel, such as a reformed hydrocarbon fuel, e.g., synthesis gas, is supplied to electrochemical cells  12  from fuel side  20  via channels (not shown) in porous substrate  14 . Although air and synthesis gas reformed from a hydrocarbon fuel are employed in the present embodiment, it will be understood that electrochemical cells using other oxidants and fuels may be employed without departing from the scope of the present invention, e.g., pure hydrogen and pure oxygen. In addition, although fuel is supplied to electrochemical cells  12  via substrate  14  in the present embodiment, it will be understood that in other embodiments of the present invention, the oxidant may be supplied to the electrochemical cells via a porous substrate. 
     Referring to  FIG. 2 , some aspects of a non-limiting example of fuel cell system  10  are described in greater detail. Fuel cell system  10  can be formed of a plurality of layers screen printed onto substrate  14 . Screen printing is a process whereby a woven mesh has openings through which the fuel cell layers are deposited onto substrate  14 . The openings of the screen determine the length and width of the printed layers. Screen mesh, wire diameter, ink solids loading and ink rheology determine the thickness of the printed layers. Fuel cell system  10  layers include an anode conductive layer  22 , an anode layer  24 , an electrolyte layer  26 , a cathode layer  28  and a cathode conductive layer  30 . In one form, electrolyte layer  26  is formed of an electrolyte sub-layer  26 A and an electrolyte sub-layer  26 B. In other embodiments, electrolyte layer  26  may be formed of any number of sub-layers. It will be understood that  FIG. 2  is not to scale; for example, vertical dimensions are exaggerated for purposes of clarity of illustration. 
     Interconnects for solid oxide fuel cells (SOFC) are preferably electrically conductive in order to transport electrons from one electrochemical cell to another; mechanically and chemically stable under both oxidizing and reducing environments during fuel cell operation; and nonporous, in order to prevent diffusion of the fuel and/or oxidant through the interconnect. If the interconnect is porous, fuel may diffuse to the oxidant side and burn, resulting in local hot spots that may result in a reduction of fuel cell life, e.g., due to degradation of materials and mechanical failure, as well as reduced efficiency of the fuel cell system. Similarly, the oxidant may diffuse to the fuel side, resulting in burning of the fuel. Severe interconnect leakage may significantly reduce the fuel utilization and performance of the fuel cell, or cause catastrophic failure of fuel cells or stacks. 
     For segmented-in-series cells, fuel cell components may be formed by depositing thin films on a porous ceramic substrate, e.g., substrate  14 . In one form, the films are deposited via a screen printing process, including the interconnect. In other embodiments, other process may be employed to deposit or otherwise form the thin films onto the substrate. The thickness of interconnect layer may be 5 to 30 microns, but can also be much thicker, e.g., 100 microns. If the interconnect is not fully nonporous, e.g., due to sintering porosity, microcracks, voids and other defects introduced during processing, gas or air flux through interconnect layer may be very high, resulting in undesirable effects, as mentioned above. Accordingly, in one aspect of the present invention, the interconnect (interconnect  16 ) is configured to minimize or eliminate diffusion of the oxidant and fuel therethrough. 
     The material of interconnect  16  of the present embodiment is a precious metal, such as Ag, Pd, Au and/or Pt and/or alloys thereof, although other materials may be employed without departing from the scope of the present invention. For example, in other embodiments, it is alternatively contemplated that other materials may be employed, including precious metal alloys, such as Ag—Pd, Ag—Au, Ag—Pt, Au—Pd, Au—Pt, Pt—Pd, Ag—Au—Pd, Ag—Au—Pt, Ag—Au—Pd—Pt and/or binary, ternary, quaternary alloys in the Pt—Pd—Au-Ag family, inclusive of alloys having minor non-precious metal additions, cermets composed of a precious metal, precious metal alloy, Ni metal and/or Ni alloy and an inert ceramic phase, such as alumina, or ceramic phase with minimum ionic conductivity which will not create significant parasitics, such as YSZ (yttria stabilized zirconia, also known as yttria doped zirconia, yttria doping is 3-8 mol %, preferably 3-5 mol %), ScSZ (scandia stabilized zirconia, scandia doping is 4-10 mol %, preferably 4-6 mol %), and/or conductive ceramics, such as conductive perovskites with A or B-site substitutions or doping to achieve adequate phase stability and/or sufficient conductivity as an interconnect, e.g., including at least one of LNF (LaNi x Fe 1-x O 3 , preferably x=0.6), LSM (La 1-x Sr x MnO 3 , x=0.1 to 0.3), doped ceria, doped strontium titanate (such as La x Sr 1-x TiO 3-δ , x=0.1 to 0.3) LSCM (La 1-x Sr x Cr 1-y Mn y O 3 , x=0.1 to 0.3 and y=0.25 to 0.75), doped yttrium chromites (such as Y 1-x Ca x CrO 3-δ , x=0.1-0.3) and/or other doped lanthanum chromites (such as La 1-x Ca x CrO 3-δ , x=0.15-0.3), and conductive ceramics, such as at least one of LNF (LaNi x Fe 1-x O 3 , preferably x=0.6), LSM (La 1-x Sr x MnO 3 , x=0.1 to 0.3), doped strontium titanate, doped yttrium chromites, LSCM (La 1-x Sr x Cr 1-y Mn y O 3 ), and other doped lanthanum chromites. In some embodiments, it is contemplated that all or part of interconnect  16  may be formed of a Ni metal cermet and/or a Ni alloy cermet in addition to or in place of the materials mentioned above. The Ni metal cermet and/or the Ni alloy cermet may have one or more ceramic phases, for example and without limitation, a ceramic phase being YSZ (yttria doping is 3-8 mol %, preferably 3-5 mol %), alumina, ScSZ (scandia doping is 4-10 mol %, preferably 4-6 mol %), doped ceria and/or TiO 2 . 
     One example of materials for interconnect  16  is y(Pd x Pt 1-x )-(1-y)YSZ. Where x is from 0 to 1 in weight ratio, preferably x is in the range of 0 to 0.5 for lower hydrogen flux. Y is from 0.35 to 0.80 in volume ratio, preferably y is in the range of 0.4 to 0.6. 
     Anode conductive layer  22  of the present embodiment is an electrode conductive layer formed of a nickel cermet, such as such as Ni-YSZ (yttria doping in zirconia is 3-8 mol %,), Ni—ScSZ (scandia doping is 4-10 mol %, preferably second doping for phase stability for 10 mol % scandia-ZrO 2 ) and/or Ni-doped ceria (such as Gd or Sm doping), doped lanthanum chromite (such as Ca doping on A site and Zn doping on B site), doped strontium titanate (such as La doping on A site and Mn doping on B site) and/or La 1-x Sr x Mn y Cr 1-y O 3 . Alternatively, it is considered that other materials for anode conductive layer  22  may be employed such as cermets based in part or whole on precious metal. Precious metals in the cermet may include, for example, Pt, Pd, Au, Ag, and/or alloys thereof. The ceramic phase may include, for example, an inactive non-electrically conductive phase, including, for example, YSZ, ScSZ and/or one or more other inactive phases, e.g., having desired coefficients of thermal expansion (CTE) in order to control the CTE of the layer to match the CTE of the substrate and electrolyte. In some embodiments, the ceramic phase may include Al 2 O 3  and/or a spinel such as NiAl 2 O 4 , MgAl 2 O 4 , MgCr 2 O 4 , NiCr 2 O 4 . In other embodiments, the ceramic phase may be electrically conductive, e.g., doped lanthanum chromite, doped strontium titanate and/or one or more forms of LaSrMnCrO. 
     One example of anode conductive layer material is 76.5% Pd, 8.5% Ni, 15%3YSZ. 
     Anode  24  may be formed of xNiO-(100-x)YSZ (x is from 55 to 75 in weight ratio), yNiO-(100-y)ScSZ (y is from 55 to 75 in weight ratio), NiO-gadolinia stabilized ceria (such as 55 wt % NiO-45 wt % GDC) and/or NiO samaria stabilized ceria in the present embodiment, although other materials may be employed without departing from the scope of the present invention. For example, it is alternatively considered that anode layer  24  may be made of doped strontium titanate, and La 1-x Sr x Mn y Cr 1-y O 3 . (such as La 0.75 Sr 0.25 Mn 0.5 Cr 0.5 O 3 ) 
     Electrolyte layer  26  of the present embodiment, e.g., electrolyte sub-layer  26 A and/or electrolyte sub-layer  26 B, may be made from a ceramic material. In one form, a proton and/or oxygen ion conducting ceramic, may be employed. In one form, electrolyte layer  26  is formed of YSZ, such as 3YSZ and/or 8YSZ. In other embodiments, electrolyte layer  26  may be formed of ScSZ, such as 4ScSZ, 6ScSz and/or 10ScSZ in addition to or in place of YSZ. In other embodiments, other materials may be employed. For example, it is alternatively considered that electrolyte layer  26  may be made of doped ceria and/or doped lanthanum gallate. In any event, electrolyte layer  26  is essentially impervious to diffusion therethrough of the fluids used by fuel cell  10 , e.g., synthesis gas or pure hydrogen as fuel, as well as, e.g., air or O 2  as an oxidant, but allows diffusion of oxygen ions or protons. 
     Cathode layer  28  may be formed at least one of LSM (La 1-x Sr x MnO 3 ,x=0.1 to 0.3), La 1-x Sr x FeO 3 , (such as x=0.3), La 1-x Sr x Co y Fe 1-y O 3  (such as La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 ) and/or Pr 1-x Sr x MnO 3  (such as Pr 0.8 Sr 0.2 MnO 3 ), although other materials may be employed without departing from the scope of the present invention. For example, it is alternatively considered that Ruddlesden-Popper nickelates and La 1-x Ca x MnO 3  (such as La 0.8 Ca 0.2 MnO 3 ) materials may be employed. 
     Cathode conductive layer  30  is an electrode conductive layer formed of a conductive ceramic, for example, at least one of LaNi x Fe 1-x O 3  (such as LaNi 0.8 Fe 0.4 O 3 ), La 1-x Sr x MnO 3  (such as La 0.75 Sr 0.25 MnO 3 ), doped lanthanum chromites (such as La 1-x Ca x CrO 3-δ , x=0.15-0.3), and/or Pr 1-x Sr x CoO 3 , such as Pr 0.8 Sr 0.2 CoO 3 . In other embodiments, cathode conductive layer  30  may be formed of other materials, e.g., a precious metal cermet, although other materials may be employed without departing from the scope of the present invention. The precious metals in the precious metal cermet may include, for example, Pt, Pd, Au, Ag and/or alloys thereof. The ceramic phase may include, for example, YSZ, ScSZ and Al 2 O 3 , or other ceramic materials. 
     One example of cathode conductive layer materials is 80 wt % Pd-20 wt % LSM. 
     In the embodiment of  FIG. 2 , various features, components and interrelationships therebetween of aspects of an embodiment of the present invention are depicted. However, the present invention is not limited to the particular embodiment of  FIG. 2  and the components, features and interrelationships therebetween as are illustrated in  FIG. 2  and described herein. 
     In the present embodiment, anode conductive layer  22  is printed directly onto substrate  14 , as is a portion of electrolyte sub-layer  26 A. Anode layer  24  is printed onto anode conductive layer  22 . Portions of electrolyte layer  26  are printed onto anode layer  24 , and portions of electrolyte layer  26  are printed onto anode conductive layer  22  and onto substrate  14 . Cathode layer  28  is printed on top of electrolyte layer  26 . Portions of cathode conductive layer  30  are printed onto cathode layer  28  and onto electrolyte layer  26 . Cathode layer  28  is spaced apart from anode layer  24  in a direction  32  by the local thickness of electrolyte layer  26 . 
     Anode layer  24  includes anode gaps  34 , which extend in a direction  36 . Cathode layer  28  includes cathode gaps  38 , which also extend in direction  36 . In the present embodiment, direction  36  is substantially perpendicular to direction  32 , although the present invention is not so limited. Gaps  34  separate anode layer  24  into a plurality of individual anodes  40 , one for each electrochemical cell  12 . Gaps  38  separate cathode layer  28  into a corresponding plurality of cathodes  42 . Each anode  40  and the corresponding cathode  42  that is spaced apart in direction  32  therefrom, in conjunction with the portion of electrolyte layer  26  disposed therebetween, form an electrochemical cell  12 . 
     Similarly, anode conductive layer  22  and cathode conductive layer  30  have respective gaps  44  and  46  separating anode conductive layer  22  and cathode conductive layer  30  into a plurality of respective anode conductor films  48  and cathode conductor films  50 . The terms, “anode conductive layer” and “anode conductor film” may be used interchangeably, in as much as the latter is formed from one or more layers of the former; and the terms, “cathode conductive layer” and “cathode conductor film” may be used interchangeably, in as much as the latter is formed from one or more layers of the former. 
     In the present embodiment, anode conductive layer  22  has a thickness, i.e., as measured in direction  32 , of approximately 5-15 microns, although other values may be employed without departing from the scope of the present invention. For example, it is considered that in other embodiments, the anode conductive layer may have a thickness in the range of 5-50 microns. In yet other embodiments, different thicknesses may be used, depending upon the particular material and application. 
     Similarly, anode layer  24  has a thickness, i.e., as measured in direction  32 , of approximately 5-20 microns, although other values may be employed without departing from the scope of the present invention. For example, it is considered that in other embodiments, the anode layer may have a thickness in the range of 5-40 microns. In yet other embodiments, different thicknesses may be used, depending upon the particular anode material and application. 
     Electrolyte layer  26 , including both electrolyte sub-layer  26 A and electrolyte sub-layer  26 B, of the present embodiment has a thickness of approximately 5-15 microns with individual sub-layer thicknesses of approximately 5 microns minimum, although other thickness values may be employed without departing from the scope of the present invention. For example, it is considered that in other embodiments, the electrolyte layer may have a thickness in the range of 5-40 microns. In yet other embodiments, different thicknesses may be used, depending upon the particular materials and application. 
     Cathode layer  28  has a thickness, i.e., as measured in direction  32 , of approximately 10-20 microns, although other values may be employed without departing from the scope of the present invention. For example, it is considered that in other embodiments, the cathode layer may have a thickness in the range of 10-50 microns. In yet other embodiments, different thicknesses may be used, depending upon the particular cathode material and application. 
     Cathode conductive layer  30  has a thickness, i.e., as measured in direction  32 , of approximately 5-100 microns, although other values may be employed without departing from the scope of the present invention. For example, it is considered that in other embodiments, the cathode conductive layer may have a thickness less than or greater than the range of 5-100 microns. In yet other embodiments, different thicknesses may be used, depending upon the particular cathode conductive layer material and application. 
     In each electrochemical cell  12 , anode conductive layer  22  conducts free electrons away from anode  24  and conducts the electrons to cathode conductive layer  30  via interconnect  16 . Cathode conductive layer  30  conducts the electrons to cathode  28 . 
     Interconnect  16  is embedded in electrolyte layer  26 , and is electrically coupled to anode conductive layer  22 , and extends in direction  32  from anode conductive layer  22  through electrolyte sub-layer  26 A toward electrolyte sub-layer  26 B, then in direction  36  from one electrochemical cell  12  to the next adjacent electrochemical cell  12 , and then in direction  32  again toward cathode conductive layer  30 , to which interconnect  16  is electrically coupled. In particular, at least a portion of interconnect  16  is embedded within an extended portion of electrolyte layer  26 , wherein the extended portion of electrolyte layer  26  is a portion of electrolyte layer  26  that extends beyond anode  40  and cathode  42 , e.g., in direction  32 , and is not sandwiched between anode  40  and cathode  42 . 
     Referring to  FIG. 3 , some aspects of a non-limiting example of interconnect  16  are described in greater detail. Interconnect  16  includes a blind primary conductor  52 , and two blind auxiliary conductors, or vias  54 ,  56 . Blind primary conductor  52  is sandwiched between electrolyte sub-layer  26 A and electrolyte sub-layer  26 B, and is formed of a body  58  extending between a blind end  60  and a blind end  62  opposite end  60 . Blind-primary conductor  52  defines a conduction path encased within electrolyte layer  26  and oriented along direction  36 , i.e., to conduct a flow of electrons in a direction substantially parallel to direction  36 . Blind auxiliary conductor  54  has a blind end  64 , and blind auxiliary conductor  56  has a blind end  66 . Blind auxiliary conductors  54  and  56  are oriented in direction  32 . As that term is used herein, “blind” relates to the conductor not extending straight through electrolyte layer  26  in the direction of orientation of the conductor, i.e., in the manner of a “blind hole” that ends in a structure, as opposed to a “through hole” that passes through the structure. Rather, the blind ends face portions of electrolyte layer  26 . For example, end  64  of conductor  54  faces portion  68  electrolyte sub-layer  26 B and is not able to “see” through electrolyte sub-layer  26 B. Similarly, end  66  of conductor  56  faces portion  70  of electrolyte sub-layer  26 A and is not able to “see” through electrolyte sub-layer  26 A. Likewise, ends  60  and  62  of body  58  face portions  72  and  74 , respectively, and are not able to “see” through electrolyte sub-layer  26 A. 
     In the embodiment of  FIG. 3 , various features, components and interrelationships therebetween of aspects of an embodiment of the present invention are depicted. However, the present invention is not limited to the particular embodiment of  FIG. 3  and the components, features and interrelationships therebetween as are illustrated in  FIG. 3  and described herein. It will be understood that  FIG. 3  is not to scale; for example, vertical dimensions are exaggerated for purposes of clarity of illustration. 
     In the present embodiment, blind primary conductor  52  is a conductive film created with a screen printing process, which is embedded within electrolyte layer  26 , sandwiched between electrolyte sub-layers  26 A and  26 B. Anode layer  24  is oriented along a first plane, cathode layer  28  is oriented along a second plane substantially parallel to the first plane, electrolyte layer  26  is oriented along a third plane substantially parallel to the first plane, and the conductive film forming blind primary conductor  52  extends in a direction substantially parallel to the first plane. 
     In one form, the material of blind primary conductor  52  may be a precious metal cermet or an electrically conductive ceramic. In other embodiments, other materials may be employed in addition to or in place of a precious metal cermet or an electrically conductive ceramic, e.g., a precious metal, such as Ag, Pd, Au and/or Pt, although other materials may be employed without departing from the scope of the present invention. In various embodiments, it is contemplated that one or more of many materials may be employed, including precious metal alloys, such as Ag—Pd, Ag—Au, Ag—Pt, Au—Pd, Au—Pt, Pt—Pd, Ag—Au—Pd, Ag—Au—Pt, and Ag—Au—Pd—Pt, cermets composed of precious metal or alloys, Ni metal and/or Ni alloy, and an inert ceramic phase, such as alumina, or ceramic phase with minimum ionic conductivity which will not generate significant parasitic current, such as YSZ, ScSZ, and/or conductive ceramics, such as at least one of LNF (LaNi x Fe 1-x O 3 ), LSM (La 1-x ,Sr x MnO 3 ), doped strontium titanate, doped yttrium chromites, LSCM (La 1-x Sr x Cr 1-y Mn y O 3 ), and/or other doped lanthanum chromites, and conductive ceramics, such as LNF (LaNi x Fe 1-x O 3 —), for example, LaNi 0.6 Fe 0.4 O 3 , LSM (La 1-x Sr x MnO 3 ), such as La 0.75 Sr 0.25 MnO 3 , doped strontium titanate, doped yttrium chromites, LSCM (La 1-x Sr x Cr 1-y Mn y O 3 ), such as La 0.75 Sr 0.25 Cr 0.5 Mn 0.5 O 3 , and other doped lanthanum chromites. In other embodiments, it is contemplated that blind primary conductor  52  may be formed of a Ni metal cermet and/or a Ni alloy cermet in addition to or in place of the materials mentioned above. The Ni metal cermet and/or the Ni alloy cermet may have one or more ceramic phases, for example and without limitation, a ceramic phase being YSZ, alumina, ScSZ, doped ceria and/or TiO 2 . In various embodiments, blind primary conductor  52  may be formed of materials set forth above with respect to interconnect  16 . 
     One example of materials for blind primary conductor  52  is y(Pd x Pt 1-x )-(1-y)YSZ. Where x is from 0 to 1 in weight ratio. For cost reduction, x is preferred in the range of 0.5 to 1. For better performance and higher system efficiency, x is preferred in the range of 0 to 0.5. Because hydrogen has higher flux in Pd. Y is from 0.35 to 0.80 in volume ratio, preferably y is in the range of 0.4 to 0.6. 
     Another example of materials for blind primary conductor  52  is x % Pd-y % Ni-(100-x-y) % YSZ, where x=70-80, y=5-10. 
     Each of blind auxiliary conductors  54  and  56  may be formed from the same or different materials than primary conductor  52 . In one form, blind auxiliary conductor  54  is formed during processing of blind primary conductor  52  and from the same material as blind primary conductor  52 , whereas blind auxiliary conductor  56  is formed at the same process step as cathode conductive layer  30  and from the same material as cathode conductive layer  30 . However, in other embodiments, blind primary conductor  52 , blind auxiliary conductor  54  and blind auxiliary conductor  56  may be made from other material combinations without departing from the scope of the present invention. 
     The materials used for blind auxiliary conductor  54  and blind auxiliary conductor  56  may vary with the particular application. For example, with some material combinations, material migration may occur at the interface of interconnect  16  with anode conductive layer  22  and/or cathode conductive layer  30  during either cell fabrication or cell testing, which may cause increased resistance at the interface and higher cell degradation during fuel cell operation. Material may migrate into primary conductor  52  from anode conductive layer  22  and/or cathode conductive layer  30 , and/or material may migrate from primary conductor  52  into anode conductive layer  22  and/or cathode conductive layer  30 , depending upon the compositions of primary conductor  52 , anode conductive layer  22  and cathode conductive layer  30 . To reduce material migration at the interconnect/conductive layer interface, one or both of blind auxiliary conductor  54  and blind auxiliary conductor  56  may be formed from a material that yields an electrically conductive chemical barrier layer between primary conductor  52  and a respective one or both of anode conductive layer  22  (anode conductor film  48 ) and/or cathode conductive layer  30  (cathode conductor film  50 ). This chemical barrier may eliminate or reduce material migration during fuel cell fabrication and operation. 
     Materials for auxiliary conductor  54  at the interconnect  16  and anode conductive layer  22  interface that may be used to form a chemical barrier may include, but are not limited to Ni cermet, Ni-precious metal cermet and the precious metal can be Ag, Au, Pd, Pt, or the alloy of them, the ceramic phase in the cermet can be at least one of YSZ (yttria doping is 3-5 mol % in zirconia), ScSZ (scandia doping is 4-6 mol % in zirconia), doped ceria (such as GDC, or SDC), alumina, and TiO 2 , or conductive ceramics, such as doped strontium titanate, doped yttrium chromites, La 1-x Sr x Cr 1-y Mn y O 3  (x=0.15-0.35, y=0.25-0.5), and other doped lanthanum chromites. 
     One example of auxiliary conductor  54  is 50 v %(50Pd50Pt)-50 v %3YSZ. 
     Another example of auxiliary conductor  54  is 15% Pd, 19% NiO, 66% NTZ, where NTZ is 73.6 wt % NiO, 20.0% TiO 2 , 6.4% 3YSZ. 
     Materials for auxiliary conductor  56  at the interconnect  16  and cathode conductive layer  30  interface that may be used to form a chemical barrier may include, but are not limited to precious metal cermets having a precious metal being at least one of: Ag, Au, Pd, Pt, or its alloy, wherein the ceramic phase may be at least one of YSZ (yttria doping is preferred from 3-5 mol %), ScSZ (scandia doping is preferred from 4-6 mol %), LNF (LaNi x Fe 1-x O 3 , x=0.6), LSM (La 1-x Sr x MnO 3 ,x=0.1 to 0.3), doped yttrium chromites (such as Y 0.8 Ca 0.2 CrO 3 ), LSCM (La 1-x Sr x Cr 1-y Mn y O 3 ), x=0.15-0.35, y=0.5-0.75), and other doped lanthanum chromites (such as La 0.7 Ca 0.3 CrO 3 ), or conductive ceramics, such as at least one of LNF (LaNi x Fe 1-x O 3 ), LSM (La 1-x Sr x MnO 3 ), Ruddlesden-Popper nickelates, LSF (such as La 0.8 Sr 0.2 FeO 3 ), LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 ), LSCM (La 1-x Sr x Cr 1-y Mn y O 3 ), LCM (such as La 0.8 Ca 0.2 MnO 3 ), doped yttrium chromites and other doped lanthanum chromites. 
     One example for auxiliary conductor  56  is 50v %(50Pd50Pt)-50v %3YSZ. 
     Another example of auxiliary conductor  56  is 15% Pd, 19% NiO, 66% NTZ, where NTZ is 73.6 wt % NiO, 20.0% TiO 2 , 6.4% 3YSZ. 
     In the present embodiment, auxiliary conductor  54  has a width  76 , i.e., in direction  36 , of approximately 0.4 mm, although greater or lesser widths may be used without departing from the scope of the present invention. Similarly, auxiliary conductor  56  has a width  78 , i.e., in direction  36 , of approximately 0.4 mm, although greater or lesser widths may be used without departing from the scope of the present invention. Primary conductor  52  has a length in direction  36  that defines a minimum diffusion distance  80  for any hydrogen that may diffuse through interconnect  16 , e.g., due to sintering porosity, microcracks, voids and/or other defects introduced into interconnect  16  during processing. In the present embodiment, diffusion distance  80  is 0.6 mm, although greater or lesser widths may be used without departing from the scope of the present invention. The film thickness  82  of primary conductor  52 , i.e., as measured in direction  32 , is approximately 5-15 microns. The total height  84  of interconnect  16  in direction  32  is approximately 10-25 microns, which generally corresponds to the thickness of electrolyte layer  26 . 
     The total diffusion distance for hydrogen diffusing through interconnect  16  may include the height of auxiliary conductor  54  and auxiliary conductor  56  in direction  32 , which may be given by subtracting from the total height  84  the film thickness  82  of primary conductor  52 , which yields approximately 10 microns. Thus, the diffusion distance is predominantly controlled by diffusion distance  80 , e.g., since the heights of auxiliary conductors  54  and  56  represent only a small fraction of the total diffusion distance. 
     Referring to  FIGS. 4A and 4B , a plan view of a continuous “strip” configuration of interconnect  16  and a plan view of a “via” configuration of interconnect  16  are respectively depicted. The term, “strip,” pertains to the configuration being in the form of a single long conductor that is comparatively narrow in width as compared to length. In the strip configuration, the primary conductor takes the form of a continuous strip  52 A extending in a direction  86  that in the present embodiment is substantially perpendicular to both directions  32  and  36 , and runs approximately the length in direction  86  of electrochemical cell  12 . In the depiction of  FIGS. 4A and 4B , direction  32  extends into and out of the plane of the drawing, and hence is represented by an “X” within a circle. The term, “via,” pertains to a relatively small conductive pathway through a material that connects electrical components. In the depiction of  FIG. 4B , the primary conductor takes the form of a plurality of vias  52 B, e.g., each having a width in direction  86  of only approximately 0.4 mm, although greater or lesser widths may be used without departing from the scope of the present invention. 
     In the embodiment of  FIGS. 4A and 4B , various features, components and interrelationships therebetween of aspects of an embodiment of the present invention are depicted. However, the present invention is not limited to the particular embodiment of  FIGS. 4A and 4B  and the components, features and interrelationships therebetween as are illustrated in  FIGS. 4A and 4B  and described herein. 
     Referring again to  FIG. 3 , in conjunction with  FIGS. 4A and 4B , the minimum diffusion area of interconnect  16  is controlled by the diffusion area of primary conductor  52 , which serves as a diffusion flow orifice that restricts the diffusion of fluid. For example, if, for any reason, primary conductor  52  is not non-porous, fluid, e.g., oxidant and fuel in liquid and/or gaseous form may diffuse through interconnect  16 . Such diffusion is controlled, in part, by the film thickness  82 . In the “strip” configuration, the diffusion area is given by the width of continuous strip  52 A in direction  86  times the film thickness  82 , whereas in the “via” configuration, the diffusion area is given by the width of each via  52 B in direction  86  times the film thickness  82  times the number of vias  52 B. 
     Although it may be possible to employ an interconnect that extends only in direction  32  from anode conductor film  48  to cathode conductor film  50  (assuming that cathode conductor film  50  were positioned above anode conductor films  48  in direction  36 ), such a scheme would result in higher leakage than were the interconnect of the present invention employed. 
     For example, referring to  FIG. 5 , some aspects of a non-limiting example of an interconnect  88  are depicted, wherein interconnect  88  in the form of a via passing through an electrolyte layer  90 , which is clearly not embedded in electrolyte layer  90  or sandwiched between sub-layers of electrolyte layer  90 , and does not include any blind conductors. Interconnect  88  transfers electrical power from an anode conductor  92  to a cathode conductor  94 . For purposes of comparison, the length  96  of interconnect  88  in direction  32 , which corresponds to the thickness of electrolyte layer  90 , is assumed to be the 10-15 microns, e.g., similar to interconnect  16 , and the width of interconnect  88 , e.g., the width of the open slot in the electrolyte  96  into which interconnect  88  is printed, in direction  36  is assumed to be the minimum printable via dimension  98  in direction  36  with current industry technology, which is approximately 0.25 mm. The length of interconnect  88  in direction  86  is assumed to be 0.4 mm. Thus, with interconnect  88 , the diffusion flow area for one via is approximately 0.25 mm times 0.4 mm, which equals 0.1 mm 2 . The limiting dimension is the minimum 0.25 mm screen printed via dimension  98 . 
     With the present invention, however, assuming via  52 B ( FIG. 4B ) to have the same length in direction  86  of 0.4 mm, the diffusion flow area for one via of 0.4 mm times the film thickness in direction  32  of 0.010 mm (10 microns) equals 0.004 mm 2 , which is only 4 percent of the flow area of interconnect  88 . Thus, by employing a geometry that allows a reduction of the minimum dimension that limits a minimum diffusion flow area, the diffusion flow area of the interconnect may be reduced, thereby potentially decreasing diffusion of oxidant and/or fuel through the interconnector, e.g., in the event the interconnect is not fully non-porous (such as, for example, due to process limitations and/or manufacturing defects), or the interconnect is a mixed ion and electronic conductor. 
     Further, the diffusion distance in interconnect  88  corresponds to the thickness  96  of interconnect  88 , which in the depicted example is also the thickness of electrolyte layer  90 , i.e., 10-15 microns. 
     In contrast, the diffusion distance of the inventive blind primary connector  52 , whether in the form of a continuous strip  52 A or a via  52 B, is diffusion distance  80 , which is 0.6 mm, and which is 40-60 times the diffusion distance of interconnect  88  (0.6 mm divided by 10-15 microns), which is many times the thickness of the electrolyte. Thus, by employing a geometry wherein the diffusion distance extends in a direction not limited by the thickness of the electrolyte, the diffusion distance of the interconnect may be substantially increased, thereby potentially decreasing diffusion of oxidant and/or fuel through the interconnector. 
     Generally, the flow of fuel and/or air through an interconnect made from a given material and microstructure depends on the flow area and flow distance. Some embodiments of the present invention may reduce fuel and/or air flow through the interconnect by 10 2  to 10 4  magnitude, e.g., if the connector is not non-porous, depending on the specific dimension of the interconnect used. 
     For example, processing-related defects such as sintering porosity, microcracks and voids are typically from sub-microns to a few microns in size (voids) or a few microns to 10 microns (microcracks). With a diffusion distance of only 10-15 microns, the presence of a defect may provide a direct flowpath through the interconnect, or at least decrease the diffusion distance by a substantial percentage. For example, assume a design diffusion distance of 10 microns. In the presence of a 10 micron defect, a direct flowpath for the flow of hydrogen and/or oxidant would occur, since such a defect would open a direct pathway through the interconnect (it is noted that the anode/conductive layer and cathode/conductive layer are intentionally porous). Even assuming a design diffusion distance of 15 microns in the presence of a 10 micron defect, the diffusion distance would be reduced by 67%, leaving a net diffusion distance of only 5 microns. 
     On the other hand, a 10 micron defect in the inventive interconnect  16  would have only negligible effect on the 0.6 mm design diffusion distance of primary conductor  52 , i.e., reducing the 0.6 mm design diffusion distance to 0.59 mm, which is a relatively inconsequential reduction caused by the presence of the defect. 
     Referring to  FIGS. 6A and 6B , some aspects of a non-limiting example of an embodiment of the present invention having a blind primary conductor in the form of a via  52 C extending in direction  86  are depicted. In the depiction of  FIG. 6A , direction  32  extends into and out of the plane of the drawing, and hence is represented by an “X” within a circle. In the depiction of  FIG. 6B , direction  36  extends into and out of the plane of the drawing, and hence is represented by an “X” within a circle. Via  52 C is similar to via  52 B, except that it extends in direction  86  rather than direction  36 , for example, as indicated by diffusion distance  80  being oriented in direction  86 . It will be understood that although  FIGS. 6A and 6B  depict only a single via  52 C, embodiments of the present invention may include a plurality of such vias extending along direction  86 . 
     The direction of electron flow in  FIGS. 6A and 6B  is illustrated by three dimensional flowpath line  100 . Electrons flow in direction  36  through anode conductor film  48  toward auxiliary conductor  54 , and then flow in direction  32  through auxiliary conductor  54  toward via  52 C. The electrons then flow in direction  86  through via  52 C toward auxiliary conductor  56 , and then flow in direction  32  through auxiliary conductor  56  into cathode conductor film  50 , after which the electrons flow in direction  36  through cathode conductor film  50 , e.g., to the next electrochemical cell. 
     In the embodiment of  FIGS. 6A and 6B , various features, components and interrelationships therebetween of aspects of an embodiment of the present invention are depicted. However, the present invention is not limited to the particular embodiment of  FIGS. 6A and 6B  and the components, features and interrelationships therebetween as are illustrated in  FIGS. 6A and 6B  and described herein. 
     Referring to  FIG. 7 , some aspects of a non-limiting example of an embodiment of a fuel cell system  210  are schematically depicted. Fuel cell system  210  includes a plurality of electrochemical cells  212  disposed on a substrate  214 , each electrochemical cell  212  having a seal in the form of a ceramic seal  102 . Fuel cell system  210  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and blind auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  214 . In the embodiment of  FIG. 7 , auxiliary conductor  56  of interconnect  16  is formed of the same material as cathode conductor film  50 , whereas auxiliary conductor  54  of interconnect  16  is formed of the same material as anode conductor film  48 . Blind primary conductor  52  of interconnect  16  is formed of the same material described above with respect to interconnect  16  in the embodiment of  FIG. 2 . In other embodiments, for example, auxiliary conductor  54  and/or auxiliary conductor  56  may be formed of the same material as blind primary conductor  52 , or may be formed of different materials. In one form, blind primary conductor  52  is in the form of a continuous strip, e.g., continuous strip  52 A depicted in  FIG. 4A . In another form, blind primary conductor  52  is in the form of a plurality of vias, such as vias  52 B in  FIG. 4B . In other embodiments, blind primary conductor  52  may take other forms not explicitly set forth herein. 
     In one form, ceramic seal  102  is applied onto porous substrate  214 , and is positioned horizontally (in the perspective of  FIG. 7 ) between the anode conductor film  48  of one electrochemical cell  212  and the auxiliary conductor  54  of the adjacent electrochemical cell  212 . In other embodiments, ceramic seal  102  may be located in other orientations and locations. Ceramic seal  102  has a thickness, i.e., as measured in direction  32 , of approximately 5-30 microns, although other thickness values may be employed in other embodiments. In one form, ceramic seal  102  is impervious to gases and liquids, such as the fuel and oxidants employed by electrochemical cells  212 , and is configured to prevent the leakage of gases and liquids from substrate  214  in those areas where it is applied. In other embodiments, ceramic seal  102  may be substantially impervious to gases and liquids, and may be configured to reduce leakage of gases and liquids from substrate  214  in those areas where it is applied, e.g., relative to other configurations that do not employ a ceramic seal. Ceramic seal  102  is configured to provide an essentially “gas-tight” seal between substrate  214  and fuel cell components disposed on the side of ceramic seal  102  opposite of that of substrate  214 . 
     In one form, ceramic seal  102  is positioned to prevent or reduce leakage of gases and liquids from substrate  214  into interconnect  16 . In one form, ceramic seal  102  extends in direction  36 , and is positioned vertically (in direction  32 ) between porous substrate  214  on the bottom and blind primary conductor  52  of interconnect  16  and electrolyte  26  on the top, thereby preventing the leakages of gases and liquids into the portions of blind primary conductor  52  (and electrolyte  26 ) that are overlapped by ceramic seal  102 . In other embodiments, ceramic seal  102  may be disposed in other suitable locations in addition to or in place of that illustrated in  FIG. 7 . Blind primary conductor  52  is embedded between a portion of ceramic seal  102  on the bottom and a portion of extended electrolyte  26  on the top. The diffusion distance in the embodiment of  FIG. 7  is primarily defined by the length of the overlap of interconnect  16  by both ceramic seal  102  and electrolyte  26  in direction  36 . In one form, the overlap is 0.3-0.6 mm, although in other embodiments, other values may be employed. Interconnect  16  extends into the active electrochemical cell  212  area. In some embodiments, the primary interconnect area of the configuration illustrated in  FIG. 7  may be smaller than other designs, which may increase the total active cell area on substrate  214 , which may increase the efficiency of fuel cell system  210 . 
     Ceramic seal  102  is formed from a ceramic material. In one form, the ceramic material used to form ceramic seal  102  is yittria stabilized zirconia, such as 3YSZ. In another form, the material used to form ceramic seal  102  is scandia stabilized zirconia, such as 4ScSZ. In another form, the material used to form ceramic seal  102  is alumina. In another form, the material used to form ceramic seal  102  is non-conductive pyrochlore materials, such as La 2 Zr 2 O 7 . Other embodiments may employ other ceramics, e.g., depending upon various factors, such as compatibility with the materials of adjacent portions of each electrochemical cell  212  and substrate  214 , the fuels and oxidants employed by fuel cell system  210 , and the local transient and steady-state operating temperatures of fuel cell system  210 . Still other embodiments may employ materials other than ceramics. 
     In the embodiment of  FIG. 7 , various features, components and interrelationships therebetween of aspects of an embodiment of the present invention are depicted. However, the present invention is not limited to the particular embodiment of  FIG. 7  and the components, features and interrelationships therebetween as are illustrated in  FIG. 7  and described herein. 
     Referring to  FIG. 8 , some aspects of a non-limiting example of an embodiment of a fuel cell system  310  are schematically depicted. Fuel cell system  310  includes a plurality of electrochemical cells  312  disposed on a substrate  314 , each electrochemical cell  312  including a ceramic seal  102 . Fuel cell system  310  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and blind auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  314 . In the embodiment of  FIG. 8 , interconnect  16  is formed predominantly by the material of anode conductor film  48 , and hence, blind primary conductor  52  and auxiliary conductor  54  in the embodiment of  FIG. 8  may be considered as extensions of anode conductor film  48 . For example, blind primary conductor  52  and auxiliary conductor  54  are depicted as being formed by the material of anode conductor film  48 , whereas auxiliary conductor  56  is formed of the materials set forth above for interconnect  16  in the embodiment of  FIG. 2 . In one form, blind primary conductor  52  is in the form of a continuous strip, e.g., continuous strip  52 A depicted in  FIG. 4A . In another form, blind primary conductor  52  is in the form of a plurality of vias, such as vias  52 B in  FIG. 4B . In other embodiments, blind primary conductor  52  may take other forms not explicitly set forth herein. 
     Ceramic seal  102  is positioned to prevent or reduce leakage of gases and liquids from substrate  314  into interconnect  16 . In one form, ceramic seal  102  is positioned vertically (in direction  32 ) between porous substrate  314  on the bottom and blind primary conductor  52  and electrolyte  26  on the top, thereby preventing the leakages of gases and liquids into the portions of blind primary conductor  52  that are overlapped by ceramic seal  102 . Blind primary conductor  52  is embedded between a portion of ceramic seal  102  on the bottom and extended electrolyte  26  on the top. The diffusion distance in the embodiment of  FIG. 8  is primarily defined by the length of the overlap of interconnect  16  by both ceramic seal  102  and electrolyte  26  in direction  36 . In one form, the overlap is 0.3-0.6 mm, although in other embodiments, other values may be employed. 
     Because ceramic seal  102  prevents the ingress of gas and liquids into electrochemical cell  312 , interconnect  16  does not need to be as dense (in order to prevent or reduce leakage) as other designs that do not include a seal, such as ceramic seal  102 . In such designs, interconnect  16  may be formed of the materials used to form anode conductor layer  48  and/or cathode conductor layer  50 . For example, referring to  FIG. 9 , an embodiment is depicted wherein interconnect  16  is formed entirely of the materials used to form anode conductor layer  48  and cathode conductor layer  50 .  FIG. 9  schematically depicts some aspects of a non-limiting example of an embodiment of a fuel cell system  410 . Fuel cell system  410  includes a plurality of electrochemical cells  412  disposed on a substrate  414 , each electrochemical cell  412  including a ceramic seal  102 . Fuel cell system  410  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and blind auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  414 . In the embodiment of  FIG. 9 , blind primary conductor  52  and auxiliary conductor  54  are formed of the same material used to form anode conductor film  48 , and are formed in the same process steps used to form anode conductor film  48 . Hence, blind primary conductor  52  and auxiliary conductor  54  in the embodiment of  FIG. 9  may be considered as extensions of anode conductor film  48 . Similarly, in the embodiment of  FIG. 9 , auxiliary conductor  56  is formed of the same material used to form cathode conductor film  50 , and is formed in the same process steps used to form cathode conductor film  50 . Hence, auxiliary conductor  56  in the embodiment of  FIG. 9  may be considered as an extension of cathode conductor film  50 . 
     In the embodiments of  FIGS. 8 and 9 , various features, components and interrelationships therebetween of aspects of embodiments of the present invention are depicted. However, the present invention is not limited to the particular embodiments of  FIGS. 8 and 9  and the components, features and interrelationships therebetween as are illustrated in  FIGS. 8 and 9  and described herein. 
     Referring to  FIGS. 10-15  generally, the inventors have determined that material diffusion between the interconnect and adjacent components, e.g., an anode and/or an anode conductor film and/or cathode and/or cathode conductor film, may adversely affect the performance of certain fuel cell systems. Hence, some embodiments of the present invention include an electrically conductive chemical barrier (e.g., as discussed above, and/or chemical barrier  104 , discussed below with respect to  FIGS. 10-15 ) to prevent or reduce such material diffusion. In various embodiments, chemical barrier  104  may be configured to prevent or reduce material migration or diffusion at the interface between the interconnect and an anode, and/or between the interconnect and an anode conductor film, and/or between the interconnect and a cathode, and/or between the interconnect and a cathode conductor film which may improve the long term durability of the interconnect. For example, without a chemical barrier, material migration (diffusion) may take place at the interface between an interconnect formed of a precious metal cermet, and an anode conductor film and/or anode formed of a Ni-based cermet. The material migration may take place in both directions, e.g., Ni migrating from the anode conductive layer/conductor film and/or anode into the interconnect, and precious metal migrating from the interconnect into the conductive layer/conductor film and/or anode. The material migration may result in increased porosity at or near the interface between the interconnect and the anode conductor film and/or anode, and may result in the enrichment of one or more non or low-electronic conducting phases at the interface, yielding a higher area specific resistance (ASR), and hence resulting in reduced fuel cell performance. Material migration between the interconnect and the cathode and/or between the interconnect and the cathode conductor film may also or alternatively result in deleterious effects on fuel cell performance. 
     Accordingly, some embodiments employ a chemical barrier, e.g., chemical barrier  104 , that is configured to prevent or reduce material migration or diffusion at the interface between the interconnect and an adjacent electrically conductive component, such as one or more of an anode, an anode conductive layer/conductor film, a cathode and/or a cathode conductive layer/conductor film, and hence prevent or reduce material migration (diffusion) that might otherwise result in deleterious effect, e.g., the formation of porosity and the enrichment of one or more non or low-electronic conducting phases at the interface. Chemical barrier  104  may be formed of one or both of two classes of materials; cermet and/or conductive ceramic. For the cermet, the ceramic phase may be one or more of an inert filler; a ceramic with low ionic conductivity, such as YSZ; and an electronic conductor. In various embodiments, e.g., for the anode side (e.g., for use adjacent to an anode and/or anode conductive layer/conductor film), chemical barrier  104  may be formed of one or more materials, including, without limitation, Ni cermet or Ni-precious metal cermet. The precious metal phase may be, for example and without limitation, one or more of Ag, Au, Pd, Pt, or one or more alloys of Ag, Au, Pd and/or Pt. The ceramic phase in the cermet may be, for example and without limitation, be at least one of YSZ (such as 3YSZ), ScSZ (such as 4ScSZ), doped ceria (such as Gd 0.1 Ce 0.9 O 2 ), SrZrO 3 , pyrochlores of the composition (M RE ) 2 Zr 2 O 7  (where M RE =one or more rare earth cations, for example and without limitation La, Pr, Nd, Gd, Sm, Ho, Er, and/or Yb), for example and without limitation, La 2 Zr 2 O 7  and Pr 2 Zr 2 O 7 , alumina, and TiO 2 , or one or more electronically conductive ceramics, such as doped ceria (higher electronic conductivity at lower oxygen partial pressure to provide low enough ASR due to thin film), doped strontium titanate, LSCM (La 1-x Sr x Cr 1-y Mn y O 3 , x=0.15-0.35, y=0.25-0.5), and/or other doped lanthanum chromites and doped yttria chromites. In various embodiments, e.g., for the cathode side (e.g., for use adjacent to a cathode and/or cathode conductive layer/conductor film), chemical barrier  104  may be formed of one or more materials, including, without limitation precious metal cermet. The precious metal phase may be, for example and without limitation, one or more of Ag, Au, Pd, Pt, or one or more alloys of Ag, Au, Pd and/or Pt. The ceramic phase in the cermet may be, for example and without limitation, be at least one of YSZ, ScSZ, doped ceria, SrZrO 3 , pyrochlores of the composition (M RE ) 2 Zr 2 O 7  (where M RE =one or more rare earth cations, for example and without limitation La, Pr, Nd, Gd, Sm, Ho, Er, and/or Yb), for example and without limitation, La 2 Zr 2 O 7  and Pr 2 Zr 2 O 7 , alumina, and TiO 2 , or one or more electronically conductive ceramics, such as LNF (LaNi x Fe 1-x O 3 , such as x=0.6) LSM (La 1-x Sr x MnO 3 , x=0.15-0.3), LCM (such as La 0.8 Ca 0.2 MnO 3 ), Ruddlesden-Popper nickelates, LSF (such as La 0.8 Sr 0.2 FeO 3 ), LSCF (La 0.6 Sr 0.4 CO 0.2 Fe 0.8 O 3 ), LSCM (La 1-x Sr x Cr 1-y Mn y O 3 , x=0.15-0.35, y=0.5-0.75) doped yttrium chromites, and other doped lanthanum chromites. The selection of the specific material(s) for chemical barrier  104  may vary with the needs of the application, e.g., depending upon cost, ease of manufacturing, the type of materials used for the component(s) electrically adjacent to interconnect  16  and/or one of its subcomponents, e.g., blind primary conductor  52 , auxiliary conductor  54  and auxiliary conductor  56 . 
     One example of anode side chemical barrier materials is 15% Pd, 19% NiO, 66% NTZ, where NTZ is 73.6 wt % NiO, 20.0% TiO 2 , 6.4% YSZ. 
     Another example of anode side chemical barrier materials is doped ceria, such as Gd 0.1 Ce 0.9 O 2 . 
     Experimental testing with a chemical barrier, such as chemical barrier  104 , in a fuel cell system yielded approximately 0.1% per thousand hour degradation rate in cell power output over the course of 1300 hours of testing using a chemical barrier formed of 30 wt % Pd-70 wt % NTZ cermet (NTZ═NiO 2 -3YSZ), disposed between an interconnect formed of 65Pd35Pt-YSZ cermet and an anode conductive layer formed of 20 wt % Pd—Ni-spinel. In a comparative test, but without the inclusion of a chemical barrier, such as chemical barrier  104 , an interconnect formed of 50 v % (96Pd6Au)-50 v % YSZ cermet directly interfacing with an anode conductive layer formed of 20 wt % Pd—Ni-spinel showed significant degradation in about 10 hours of testing, and fuel cell failure at about 25 hours of testing resulting from material migration between the interconnect and the anode conductive layer. In another test, two fuel cells were tested using a chemical barrier  104  formed of a conductive ceramic (10 mol % Gd doped CeO 2 ) disposed between disposed between an anode conductor film and an interconnect. ASR for the interconnect showed no degradation after approximately 8000 hours of testing, and instead showed slight improvement, yielding final values of 0.05 ohm-cm 2  and 0.06 ohm-cm 2  in the two test articles. 
     Referring to  FIG. 10 , some aspects of a non-limiting example of an embodiment of a fuel cell system  510  disposed on a substrate  514  are schematically depicted. Fuel cell system  510  includes a chemical barrier  104 . Fuel cell system  510  also includes some the components set forth above and described with respect to fuel cell system  10 , e.g., including an interconnects  16  having a blind primary conductor  52 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; and cathodes  42 . Although only a single instance of interconnect  16 , blind primary conductor  52 , anode  40  and cathode  42  are depicted, and two instances of electrolyte layers  26  are depicted, it will be understood that fuel cell system  510  may include a plurality of each such components, e.g., arranged in series in direction  36 , e.g., similar to embodiments described above. The description of substrate  14  applies equally to substrate  514 . In fuel cell system  510 , chemical barrier  104  is disposed between anode  40  and interconnect  16  (blind primary conductor  52 ), extending in direction  32  between anode  40  and interconnect  16 , and is configured to prevent material migration between anode  40  and interconnect  16  (blind primary conductor  52 ). Chemical barrier  104  may be formed from one or more of the materials set forth above with respect to the embodiments of  FIGS. 10-15 . 
     Referring to  FIG. 11 , some aspects of a non-limiting example of an embodiment of a fuel cell system  610  are schematically depicted. Fuel cell system  610  includes a plurality of electrochemical cells  612  disposed on a substrate  614 , each electrochemical cell  612  including a chemical barrier  104 . Fuel cell system  610  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and blind auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  614 . In fuel cell system  610 , chemical barrier  104  is disposed between anode conductor film  48  and interconnect  16  (blind primary conductor  52 ), extending in direction  32  between anode conductor film  48  and interconnect  16 , and is configured to prevent material migration between anode conductor film  48  and interconnect  16  (blind primary conductor  52 ). Chemical barrier  104  may be formed from one or more of the materials set forth above with respect to the embodiments of  FIGS. 10-15 . In fuel cell system  610 , a portion of electrolyte layer  26  is disposed between anode  40  and chemical barrier  104 , extending in direction  36  between anode  40  and chemical barrier  104 . 
     Referring to  FIG. 12 , some aspects of a non-limiting example of an embodiment of a fuel cell system  710  are schematically depicted. Fuel cell system  710  includes a plurality of electrochemical cells  712  disposed on a substrate  714 , each electrochemical cell  712  including a ceramic seal  102  and a chemical barrier  104 . Fuel cell system  710  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and blind auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  714 . In fuel cell system  710 , ceramic seal  102  is positioned to prevent or reduce leakage of gases and liquids from substrate  714  into interconnect  16  (blind interconnect  52 ), and extends in direction  36  between the anode conductor film  48  of one electrochemical cell  712  and the auxiliary conductor  54  of an adjacent electrochemical cell  712 . 
     In fuel cell system  710 , ceramic seal  102  is positioned vertically (in direction  32 ) between porous substrate  714  on the bottom and blind primary conductor  52  of interconnect  16  and electrolyte  26  on the top, thereby preventing the leakages of gases and liquids from substrate  714  into the portions of blind primary conductor  52  (and electrolyte  26 ) that are overlapped by ceramic seal  102 . In other embodiments, ceramic seal  102  may be disposed in other suitable locations in addition to or in place of that illustrated in  FIG. 12 . Ceramic seal  102  may be formed of one or more of the materials set forth above with respect to the embodiment of  FIG. 7 . A portion of blind primary conductor  52  is embedded between ceramic seal  102  on the bottom and electrolyte  26  on the top. The diffusion distance in the embodiment of  FIG. 12  is primarily defined by the length of the overlap of blind primary conductor  52  by both ceramic seal  102  and electrolyte  26  in direction  36 . 
     In fuel cell system  710 , chemical barrier  104  is disposed between anode conductor film  48  and interconnect  16  (blind primary conductor  52 ), extending in direction  32  between anode conductor film  48  and both blind primary conductor  52  and auxiliary conductor  54  of interconnect  16 , and is configured to prevent material migration between anode conductor film  48  and blind primary conductor  52  and auxiliary conductor  54 . Chemical barrier  104  may be formed from one or more of the materials set forth above with respect to the embodiments of  FIGS. 10-15 . 
     Referring to  FIG. 13 , some aspects of a non-limiting example of an embodiment of a fuel cell system  810  are schematically depicted. Fuel cell system  810  includes a plurality of electrochemical cells  812  disposed on a substrate  814 , each electrochemical cell  812  including a ceramic seal  102  and a chemical barrier  104 . Fuel cell system  810  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  814 . 
     In fuel cell system  810 , ceramic seal  102  is positioned to prevent or reduce leakage of gases and liquids from substrate  814  into interconnect  16  (blind interconnect  52 ), and extends in direction  36  between the anode  40  and anode conductor film  48  of one electrochemical cell  812  and the anode  40  and anode conductor film  48  of an adjacent electrochemical cell  812 . In fuel cell system  810 , ceramic seal  102  is positioned vertically (in direction  32 ) between porous substrate  814  on the bottom and blind primary conductor  52  of interconnect  16  and electrolyte  26  on the top, thereby preventing the leakages of gases and liquids from substrate  714  into the portions of blind primary conductor  52  (and electrolyte  26 ) that are overlapped by ceramic seal  102 . In other embodiments, ceramic seal  102  may be disposed in other suitable locations in addition to or in place of that illustrated in  FIG. 13 . Ceramic seal  102  may be formed of one or more of the materials set forth above with respect to the embodiment of  FIG. 7 . A portion of blind primary conductor  52  is embedded between ceramic seal  102  on the bottom, and electrolyte  26  on the top. The diffusion distance in the embodiment of  FIG. 13  is primarily defined by the length of the overlap of blind primary conductor  52  by both ceramic seal  102  and electrolyte  26  in direction  36 . 
     In fuel cell system  810 , chemical barrier  104  is disposed between anode  40  and blind primary conductor  52 , and is configured to prevent material migration between anode  40  and blind primary conductor  52 . In one form, chemical barrier  104  also functions as auxiliary conductor  54 . In other embodiments, auxiliary conductor  54  may be formed separately from chemical barrier  104 . Chemical barrier  104  may be formed from one or more of the materials set forth above with respect to the embodiments of  FIGS. 10-15 . 
     Referring to  FIG. 14 , some aspects of a non-limiting example of an embodiment of a fuel cell system  910  disposed on a substrate  914  are schematically depicted. Fuel cell system  910  includes a chemical barrier  104 . Fuel cell system  910  also includes some the components set forth above and described with respect to fuel cell system  10 , e.g., including an interconnects  16  having a blind primary conductor  52 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; and cathodes  42 . Although only a single instance of interconnect  16 , blind primary conductor  52 , anode  40  and cathode  42  are depicted, and two instances of electrolyte layers  26  are depicted, it will be understood that fuel cell system  910  may include a plurality of each such components, e.g., arranged in series in direction  36 , e.g., similar to embodiments described above. The description of substrate  14  applies equally to substrate  914 . In fuel cell system  910 , chemical barrier  104  is disposed between cathode  42  and interconnect  16  (blind primary conductor  52 ), extending in direction  32  between cathode  42  and interconnect  16 , and is configured to prevent material migration between cathode  42  and interconnect  16  (blind primary conductor  52 ). Chemical barrier  104  may be formed from one or more of the materials set forth above with respect to the embodiments of  FIGS. 10-15 . 
     Referring to  FIG. 15 , some aspects of a non-limiting example of an embodiment of a fuel cell system  1010  are schematically depicted. Fuel cell system  1010  includes a plurality of electrochemical cells  612  disposed on a substrate  1014 , each electrochemical cell  1012  including a chemical barrier  104 . Fuel cell system  1010  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and blind auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  1014 . In fuel cell system  1010 , chemical barrier  104  is disposed between cathode conductor film  50  and interconnect  16  (blind primary conductor  52 ), extending in direction  32  between cathode conductor film  50  and interconnect  16  (blind primary conductor  52 ), and is configured to prevent material migration between cathode conductor film  50  and interconnect  16  (blind primary conductor  52 ). Chemical barrier  104  may be formed from one or more of the materials set forth above with respect to the embodiments of  FIGS. 10-15 . In the embodiment of  FIG. 15 , chemical barrier  104  also functions as auxiliary conductor  56 . 
     In the embodiments of  FIGS. 10-15 , various features, components and interrelationships therebetween of aspects of embodiments of the present invention are depicted. However, the present invention is not limited to the particular embodiments of  FIGS. 10-15  and the components, features and interrelationships therebetween as are illustrated in  FIGS. 10-15  and described herein. 
     Referring to  FIGS. 16-19  generally, the inventors have determined that in some fuel cells, under some operating conditions, the cathode conductive layer/conductor film, the electrolyte, and portions of the interconnect, e.g., vias, can form parasitic cells within or between each electrochemical cell, particularly where there is overlap between the cathode conductive layer/conductor film and the electrolyte. In the parasitic cells, the cathode conductive layer/conductor film functions as a cathode, and the interconnect, e.g., vias formed of precious metal cermet, function as an anode. The parasitic cells consume fuel during fuel cell operation, thereby reducing the efficiency of the fuel cell system. In addition, the steam generated by the parasitic cells may create local high oxygen partial pressure that may result in the oxidation of Ni that may have diffused into precious metal phase of the interconnect (e.g., via) materials, resulting in degradation of the interconnect. 
     The inventors performed tests that confirmed the existence of parasitic cells. The tests confirmed that, although significant degradation did not occur at some temperatures, e.g., 900° C., under the testing times, degradation of the interconnect occurred at higher operating temperatures, e.g., 925° C. after approximately 700 hours of testing. Post test analysis showed Ni migration from the anode conductive layer/conductor film side to the cathode conductive layer/conductor film side of the interconnect through the precious metal phase in blind primary conductor  52 , which was accelerated by the higher operating temperature. A high oxygen partial pressure resulting from steam formed by the parasitic cells caused Ni oxidation at the interface of extended electrolyte  26  and blind primary interconnect  52  near the boundary between the cathode conductive layer/conductor film and the electrolyte, which segregated from the precious metal of the interconnect. Continued NiO accumulation at the interface between the blind primary conductor  52  and the electrolyte  26 , and continued Ni migration would likely result in failure of the interconnect. 
     In order to prevent overlap between the cathode conductive layer/conductor film and the electrolyte, in various embodiments the inventors employed a separation feature (gap  106  of  FIGS. 16 and 17 ; and insulator  108  of  FIGS. 18 and 19 ) between the cathode conductive layer/conductor film and the electrolyte to separate, i.e., space apart, the cathode conductive layer/conductor film and the electrolyte from contacting each other, thus eliminating the parasitic cells. Testing of fuel cell systems with a separation feature in the form of gap  106  (and also including a chemical barrier  104  formed of Pd—Ni alloy cermet) for approximately 2000 hours, including approximately 1000 hours at aggressive conditions (925° C. and fuel consisting of 20% H 2 , 10% CO, 19% CO 2 , 47% steam and 4% N 2 ) did not result in degradation of the interconnect. Accordingly, some embodiments of the present invention include a separation feature, e.g., gap  106 , between the cathode conductive layer/conductor film and the electrolyte, which prevents the establishment of parasitic cells. 
     Referring to  FIG. 16 , some aspects of a non-limiting example of an embodiment of a fuel cell system  1110  are schematically depicted. Fuel cell system  1110  includes a plurality of electrochemical cells  1112  disposed on a substrate  1114 , each electrochemical cell  1112  including a ceramic seal  102 , a chemical barrier  104 , and a separation feature in the form of gap  106 . Fuel cell system  1110  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and blind auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  1114 . Gap  106  extends in direction  36  between cathode conductor film  50  (e.g., formed of one or more cathode conductive layers  30 ) and electrolyte layer  26 . 
     In fuel cell system  1110 , ceramic seal  102  is positioned to prevent or reduce leakage of gases and liquids from substrate  1114  into interconnect  16  (blind primary conductor  52 ), and extends in direction  36  between the anode conductor film  48  of one electrochemical cell  1112  and the auxiliary conductor  54  of an adjacent electrochemical cell  1112 . 
     In fuel cell system  1110 , ceramic seal  102  is positioned vertically (in direction  32 ) between porous substrate  1114  on the bottom and blind primary conductor  52  of interconnect  16  and electrolyte  26  on the top, thereby preventing the leakages of gases and liquids from substrate  1114  into the portions of blind primary conductor  52  (and electrolyte  26 ) that are overlapped by ceramic seal  102 . In other embodiments, ceramic seal  102  may be disposed in other suitable locations in addition to or in place of that illustrated in  FIG. 12 . Ceramic seal  102  may be formed of one or more of the materials set forth above with respect to the embodiment of  FIG. 7 . A portion of blind primary conductor  52  is embedded between ceramic seal  102  on the bottom, and extended electrolyte  26  on the top. The diffusion distance in the embodiment of  FIG. 16  is primarily defined by the length of the overlap of blind primary conductor  52  by both ceramic seal  102  and electrolyte  26  in direction  36 . 
     In fuel cell system  1110 , chemical barrier  104  is disposed between anode conductor film  48  and interconnect  16  (blind primary conductor  52 ), extending in direction  32  between anode conductor film  48  and both blind primary conductor  52  and auxiliary conductor  54  of interconnect  16 , and is configured to prevent material migration between anode conductor film  48  and blind primary conductor  52  and auxiliary conductor  54 . Chemical barrier  104  may be formed from one or more of the materials set forth above with respect to the embodiments of  FIGS. 10-15 . 
     In fuel cell system  1110 , gap  106  is configured to prevent formation of a parasitic fuel cell between cathode conductor film  50 , electrolyte layer  26  and blind primary conductor  52 . Although gap  106  in the embodiment of  FIG. 16  is employed in conjunction with a fuel cell system having ceramic seal  102 , chemical barrier  104  and anode conductor film  48 , in other embodiments, gap  106  may be employed in fuel cell systems that do not include components corresponding to one or more of ceramic seal  102 , chemical barrier  104  and anode conductor film  48 . 
     Referring to  FIG. 17 , some aspects of a non-limiting example of an embodiment of a fuel cell system  1210  are schematically depicted. Fuel cell system  1210  includes a plurality of electrochemical cells  1212  disposed on a substrate  1214 , each electrochemical cell  1212  including a chemical barrier  104  and a separation feature in the form of gap  106 . Fuel cell system  1210  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and blind auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  1214 . 
     In fuel cell system  1210 , chemical barrier  104  is disposed between anode conductor film  48  and interconnect  16  (blind primary conductor  52 ), extending in direction  32  between anode conductor film  48  and interconnect  16 , and is configured to prevent material migration between anode conductor film  48  and interconnect  16  (blind primary conductor  52 ). Chemical barrier  104  may be formed from one or more of the materials set forth above with respect to the embodiments of  FIGS. 10-15 . In fuel cell system  1210 , a portion of electrolyte layer  26  is disposed between anode  40  and chemical barrier  104 , extending in direction  36  between anode  40  and chemical barrier  104 . 
     In fuel cell system  1210 , gap  106  is configured to prevent formation of a parasitic fuel cell between auxiliary conductor  56  (formed of the same material as cathode conductor film  50 ), electrolyte layer  26  and blind primary conductor  52 . Although gap  106  in the embodiment of  FIG. 17  is employed in conjunction with a fuel cell system having chemical barrier  104  and anode conductor film  48 , in other embodiments, gap  106  may be employed in fuel cell systems that do not include components corresponding to one or more of chemical barrier  104  and anode conductor film  48 . 
     Referring to  FIG. 18 , some aspects of a non-limiting example of an embodiment of a fuel cell system  1310  are schematically depicted. Fuel cell system  1310  includes a plurality of electrochemical cells  1312  disposed on a substrate  1314 , each electrochemical cell  1312  including a ceramic seal  102 , a chemical barrier  104 , and a separation feature in the form of an insulator  108 . Fuel cell system  1310  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and blind auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  1314 . Insulator  108  extends in direction  36  between cathode conductor film  50  (e.g., formed of one or more cathode conductive layers  30 ) and electrolyte layer  26 . 
     In fuel cell system  1310 , ceramic seal  102  is positioned to prevent or reduce leakage of gases and liquids from substrate  1314  into interconnect  16  (blind primary conductor  52 ), and extends in direction  36  between the anode conductor film  48  of one electrochemical cell  1312  and the auxiliary conductor  54  of an adjacent electrochemical cell  1312 . 
     In fuel cell system  1310 , ceramic seal  102  is positioned vertically (in direction  32 ) between porous substrate  1314  on the bottom and blind primary conductor  52  of interconnect  16  and electrolyte  26  on the top, thereby preventing the leakages of gases and liquids from substrate  1314  into the portions of blind primary conductor  52  (and electrolyte  26 ) that are overlapped by ceramic seal  102 . In other embodiments, ceramic seal  102  may be disposed in other suitable locations in addition to or in place of that illustrated in  FIG. 12 . Ceramic seal  102  may be formed of one or more of the materials set forth above with respect to the embodiment of  FIG. 7 . A portion of blind primary conductor  52  is embedded between ceramic seal  102  on the bottom, and extended electrolyte  26  on the top. The diffusion distance in the embodiment of  FIG. 18  is primarily defined by the length of the overlap of blind primary conductor  52  by both ceramic seal  102  and electrolyte  26  in direction  36 . 
     In fuel cell system  1310 , chemical barrier  104  is disposed between anode conductor film  48  and interconnect  16  (blind primary conductor  52 ), extending in direction  32  between anode conductor film  48  and both blind primary conductor  52  and auxiliary conductor  54  of interconnect  16 , and is configured to prevent material migration between anode conductor film  48  and blind primary conductor  52  and auxiliary conductor  54 . Chemical barrier  104  may be formed from one or more of the materials set forth above with respect to the embodiments of  FIGS. 10-15 . 
     In fuel cell system  1310 , insulator  108  is configured to prevent formation of a parasitic fuel cell between cathode conductor film  50 , electrolyte layer  26  and blind primary conductor  52 . In one form, insulator  108  is formed from an insulating non-conductive materials, such as aluminum oxide (Al 2 O 3 ), pyrochlore, such as In other embodiments, La 2 Zr 2 O 7 , Pr 2 Zr 2 O 7 , and SrZrO 3 . other materials may be employed to form insulator  108 , e.g., one or more other types of non-conducting ceramics in addition to or in place of aluminum oxide. Although insulator  108  in the embodiment of  FIG. 16  is employed in conjunction with a fuel cell system having ceramic seal  102 , chemical barrier  104  and anode conductor film  48 , in other embodiments, insulator  108  may be employed in fuel cell systems that do not include components corresponding to one or more of ceramic seal  102 , chemical barrier  104  and anode conductor film  48 . 
     Referring to  FIG. 19 , some aspects of a non-limiting example of an embodiment of a fuel cell system  1410  are schematically depicted. Fuel cell system  1410  includes a plurality of electrochemical cells  1412  disposed on a substrate  1414 , each electrochemical cell  1412  including a chemical barrier  104  and a separation feature in the form of insulator  108 . Fuel cell system  1410  also includes the components set forth above and described with respect to fuel cell system  10 , e.g., including interconnects  16  having blind primary conductors  52  and blind auxiliary conductors or vias  54  and  56 ; an oxidant side  18 ; a fuel side  20 ; electrolyte layers  26 ; anodes  40 ; cathodes  42 , anode conductor films  48  and cathode conductor films  50 . The description of substrate  14  applies equally to substrate  1414 . 
     In fuel cell system  1410 , chemical barrier  104  is disposed between anode conductor film  48  and interconnect  16  (blind primary conductor  52 ), extending in direction  32  between anode conductor film  48  and interconnect  16 , and is configured to prevent material migration between anode conductor film  48  and interconnect  16  (blind primary conductor  52 ). Chemical barrier  104  may be formed from one or more of the materials set forth above with respect to the embodiments of  FIGS. 10-15 . In fuel cell system  1410 , a portion of electrolyte layer  26  is disposed between anode  40  and chemical barrier  104 , extending in direction  36  between anode  40  and chemical barrier  104 . 
     In fuel cell system  1410 , insulator  108  is configured to prevent formation of a parasitic fuel cell between auxiliary conductor  56  (formed of the same material as cathode conductor film  50 ), electrolyte layer  26  and blind primary conductor  52 . Insulator  108  may be formed of the materials set forth above in the embodiment of  FIG. 18 . Although insulator  108  in the embodiment of  FIG. 19  is employed in conjunction with a fuel cell system having chemical barrier  104  and anode conductor film  48 , in other embodiments, insulator  108  may be employed in fuel cell systems that do not include components corresponding to one or more of chemical barrier  104  and anode conductor film  48 . 
     In the embodiments of  FIGS. 16-19 , various features, components and interrelationships therebetween of aspects of embodiments of the present invention are depicted. However, the present invention is not limited to the particular embodiments of  FIGS. 16-19  and the components, features and interrelationships therebetween as are illustrated in  FIGS. 16-19  and described herein. 
     As mentioned above with respect to  FIGS. 16-19 , under certain conditions, parasitic cells may be undesirably formed. The embodiments discussed above with respect to  FIGS. 16-19  provide certain approaches to resolving the parasitic cell problem. The inventors have also created other approaches to solving the parasitic cell problem, based on material selection, e.g., the material from which the interconnect and/or vias (e.g., interconnect  16 , including blind primary conductor  52 , auxiliary conductor  54  and/or auxiliary conductor  56 , and/or other interconnect and/or via configurations not mentioned herein) are formed. In one form, for an alternate cermet material, precious metal-La 2 Zr 2 O 7  pyrochlore cermet may be employed for primary interconnect material for segmented-in-series fuel cell, or via material for multi-layer ceramic interconnect. In the such a cermet material, La 2 Zr 2 O 7  pyrochlore could fully replace doped zirconia, or partially replace doped zirconia to keep ionic phase below its percolation to eliminate or reduce ionic conduction. 
     In one form, the composition of the interconnect and/or via(s), e.g., one or more of the previously mentioned compositions for the interconnect and/or via(s), is altered to include non-ionic conducting ceramic phases in the composition of the interconnect and/or via(s). 
     For example, in one form, the interconnect and/or via may be formed, all or in part, of a cermet, such as those previously described with respect to interconnect  16 , including blind primary conductor  52 , auxiliary conductor  54  and/or auxiliary conductor  56 , but also or alternatively including one or more non-ionic conductive ceramic phases. Examples include, without limitation, SrZrO 3 , La 2 Zr 2 O 7  pyrochlore, Pr 2 Zr 2 O 7  pyrochlore, BaZrO 3 , MgAl 2 O 4  spinel, NiAl 2 O 4  spinel, MgCr 2 O 4  spinel, NiCr 2 O 4  spinel, Y 3 Al 5 O 12  and other garnets with various A- and B-site substitution, and alumina. Other non-ionic conductive ceramic phases are also contemplated herein in addition to or in place of the examples set forth herein. Considerations for materials may include the coefficient of thermal expansion of the ceramic phase(s), e.g., relative to the coefficient thermal expansion of the porous substrate. In some embodiments, preferred materials for chemical compatibility with adjacent fuel cell layers may include precious metal-pyrochlore cermets, wherein the general class of pyrochlores is (M RE ) 2 Zr 2 O 7 , wherein M RE  is a rare earth cation, for example and without limtiation La, Pr, Nd, Gd, Sm, Ho, Er, and/or Yb. 
     In other embodiments, nonionic phases such as SrZrO 3 , MgAl 2 O 4  spinel, NiAl 2 O 4  spinel, alumina and pyrochlore compositions partially or completely replace the ionic conducting YSZ, e.g., of previously described interconnects and/or vias. Preferably, pyrochlore powders and/or one or more of the other nonionic phases replace YSZ sufficiently to render the balance of the YSZ to be below a percolation threshold to eliminate ionic conductivity across the interconnect/via. The YSZ volume fraction of the via is purposely reduced to less than 30v % to minimize any ionic conductivity within the via material. 
     In one form, the composition of the interconnect and/or via(s), e.g., one or more of the previously mentioned compositions for the interconnect and/or via(s), is altered to include a reactant phase to form non-ionic conducting ceramic phases during firing of the fuel cell, e.g., by the inclusion of rare earth oxides in the compound used to form the interconnect/via(s). 
     For example, in some embodiments, all or portions interconnect  16  or other interconnects or vias may include a reactant phase in the form of rare earth oxide, e.g., within the screen printing ink, at less than the stoichiometric ratio to form pyrochlore being one mole of the oxides of La, Pr, Nd, Gd, Sm, Ho, Er, Yb to two moles of the zirconia content of the via. In the overall cermet composition (e.g., cermet compositions for all or part of interconnect  16  set forth herein) which reacts with the YSZ during firing of the fuel cell to form pyrochlore within the interconnect/via and adjacent to the electrolyte, e.g., electrolyte  26 . In one form, the minimum rare earth oxide required is about 13 mole % ceramic composition in order to reduce YSZ phase below 30v % percolation. In other embodiments, other rare earth oxide amounts may be employed. The zirconia phase may still be able to exist at greater than the percolation threshold, since the insulating pyrochlore phase could form along grain boundaries. However, in some embodiments, it would be preferable to add sufficient rare earth oxides to take the YSZ phase content to below the percolation threshold on a bulk composition basis. Similar to the pyrochlores, SrZrO 3  nonionic phases could be created in-situ through addition of SrO powder as a reactant phase, e.g., to the interconnect inks, at less than the stoichimetric ratio of 1 mole SrO to 1 mole ZrO 2 . 
     In still other embodiments, all or portions interconnect  16  or other interconnects or vias may include a content of rare earth oxide, e.g., within the screen printing ink, at greater than the stoichiometric ratio of pyrochlore being one mole of the oxides, e.g., of La, Pr, Nd, Gd, Sm, Ho, Er, and/or Yb, to two moles of the zirconia content of the via in the overall cermet composition (e.g., cermet compositions for all or part of interconnect  16  set forth herein) which reacts with the YSZ during firing of the fuel cell to form pyrochlore within the interconnect/via, and the unreacted rare earth oxide will further react with the extended electrolyte in the vicinity of the interconnect during electrolyte firing to form a pyrochlore film on the electrolyte surface, e.g., on the surface of electrolyte  26 , which will sufficiently disrupt the pathways for oxygen ionic conductivity. In form, the rare earth oxide amount is from 33 mole % to 50 mole % based on the total ceramic phase. In other embodiments, other rare earth oxide amounts may be employed. The excess rare earth oxide may ensure the absence of ionic conductivity. However, too much excess rare earth remaining within the interconnect/via could cause the via to be susceptible to moisture induced damage on phase change to the rare earth hydroxides. Hence, it is desirable in some embodiments to limit the amount of rare earth oxides to less than 10% over the stoichiometric ratio. Similar to the pyrochlores, SrZrO 3  nonionic phases could be created in-situ within the via and adjacent extended electrolyte through addition of SrO powder to the interconnect inks in excess of the stoichimetric ratio of 1 mole SrO to 1 mole ZrO 2 . In one form, a lower limit is approximately 15-20 mole % SrO based on the ceramic phase, in order to form SrZrO3 to reduce YSZ below the percolation threshold. In other embodiments, other lower limits may apply. In one form, an upper limit is about 50-60 mole % SrO based on the ceramic phase (SrO+ZrO2). In other embodiments, other upper limits may apply. 
     In yet still other embodiments, all or portions interconnect  16  or other interconnects or vias may include a content of rare earth oxide at the stoichiometric ratio with YSZ to lead to full reactivity to (M RE ) 2 Zr 2 O 7 . 
     Firing temperatures for using a reactant phase to form the non-ionic conducting ceramic phases during firing of the fuel cell may vary with the needs of the particular application. Considerations include, for example and without limitation, the sinterability of different materials, powder particle size, specific surface area. Other material and/or processing parameters may also affect the selected firing temperature. For example, If the temperature is too low, the electrolyte may have higher porosity and cause leakage. If the temperature is too high, it may cause other issues, such as too high an anode density, which may reduce electrochemical activity, or may cause substrate dimensional changes, etc. Hence, the actual firing temperature for purposes of using one or more reactant phases to form one or more non-ionic conducting ceramic phases may vary as between applications. In one form, the firing temperature may be 1385° C. In some embodiments, the firing temperature may be in the range of 1370° C. to 1395° C. In other embodiments, the firing temperature may be in the range of 1350° C. to 1450° C. In still other embodiments, the firing temperature may be outside the range of 1350° C. to 1450° C. Processing steps to form the one or more non-ionic conducting ceramic phases may include preparing a composition including the rare earth oxide, YSZ and a precious metal, forming the interconnect/via(s), firing the composition at the desired temperature, e.g., at a temperature or within a temperature range set forth above, and holding the composition at the firing temperature for a desired period, e.g., in the range of 1-5 hours. In embodiments wherein all or portions of the fuel cell are formed by screen printing, the method may include preparing a screen printable ink that incorporates the rare earth oxide, YSZ and the precious metal; printing the interconnect/via(s); drying the ink; firing the printed interconnect/via(s) at the desired temperature, e.g., at a temperature or within a temperature range set forth above; and holding the composition at the firing temperature for a desired period, e.g., in the range of 1-5 hours. 
     In additional embodiments, other non-ionic conducting phases or reactant phases may be employed to minimize the ionic conductivity of the interconnect. 
     The following Tables 1-8 provide compositional information for some aspects of non-limiting experimental fuel cell and fuel cell component examples produced in accordance with some aspects of some embodiments of the present invention. It will be understood the present invention is in no way limited to the examples provided below. The columns entitled “General Composition” illustrate some potential compositional ranges, including some preferred ranges, for some materials described herein, whereas, the columns entitled “Specific Composition” illustrates the materials used in the test articles/materials. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 (w/o ceramic seal) 
               
            
           
           
               
               
               
            
               
                   
                 General Composition 
                 Specific Composition 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 Anode 
                 NiO—YSZ (NiO = 55-75 wt %) 
                   
               
               
                 Anode conductive layer 
                 Pd—Ni—YSZ 
               
               
                 Cathode 
                 La (1−x) Sr x MnO (3−d) (x = 0.1-0.3) —3YSZ 
               
               
                 Cathode conductive layer 
                 Pd—La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3) 
               
               
                 Electrolyte 
                 3YSZ 
                 3YSZ 
               
               
                 Blind primary conductor 
                   x Pd(100 − x)Pt—YSZ (x = 35-65 wt ratio, 
                 31.1%Pd, 31.1%Pt, 24.4% 3YSZ 
               
               
                   
                 alloy is 35-80 v %) 
               
               
                 Auxiliary conductor on anode side 
                   x Pd(100 − x)Pt—YSZ (x = 35-65 wt ratio, 
                 31.1%Pd, 31.1%Pt, 24.4% 3YSZ 
               
               
                   
                 alloy is 35-80 v %) 
               
               
                 Auxiliary conductor on cathode side 
                 Pd—La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3) 
               
               
                 Substrate 
                 MgO—MgAl 2 O 4   
                 69.4%MgO, 30.6%MgAl 2 O 4   
               
               
                 Substrate surface modification layer 
                 3-8 mol %Y 2 O 3 —ZrO 2   
                 8YSZ 
               
               
                 Ceramic seal 
                 N/A 
                 N/A 
               
               
                 Cell ASR, ohm-cm{circumflex over ( )}2 
                   
                  0.375 
               
               
                 Interconnect ASR, ohm-cm{circumflex over ( )}2 
                   
                  0.027 
               
               
                 Test duration, hrs 
                   
                 860 
               
               
                   
               
               
                 Examples: TCT23 (STC13-3): blind primary interconnect is long strip design FIG. 4 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 (w/o ceramic seal) 
               
            
           
           
               
               
               
            
               
                   
                 General Composition 
                 Specific Composition 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 Anode 
                 NiO—YSZ (NiO = 55-75 wt %) 
                   
               
               
                 Anode conductive layer 
                 Pd—Ni—YSZ 
               
               
                 Cathode 
                 La (1−x) Sr x MnO (3−d) (x = 0.1-0.3) —3YSZ 
               
               
                 Cathode conductive layer 
                 Pd—La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3) 
               
               
                 Electrolyte 
                 3YSZ 
                 3YSZ 
               
               
                 Blind primary conductor 
                   x Pd(100 − x)Pt—YSZ (x = 35-65 wt ratio, 
                 31.1%Pd, 31.1%Pt, 24.4% 3YSZ 
               
               
                   
                 alloy is 35-80 v %) 
               
               
                 Auxiliary conductor on anode side 
                   x Pd(100 − x)Pt—YSZ (x = 35-65 wt ratio, 
                 31.1%Pd, 31.1%Pt, 24.4% 3YSZ 
               
               
                   
                 alloy is 35-80 v %) 
               
               
                   
                 Pd—La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3) 
               
               
                 Substrate 
                 MgO−MgAl 2 O 4   
                 69.4%MgO, 30.6%MgAl 2 O 4   
               
               
                 Substrate surface modification layer 
                 3-8 mol %Y 2 O 3 —ZrO 2   
                 8YSZ 
               
               
                 Ceramic seal 
                   
                 N/A 
               
               
                 cell ASR, ohm-cm{circumflex over ( )}2 
                   
                   0.30 
               
               
                 Interconnect ASR, ohm-cm{circumflex over ( )}2 
                   
                   0.02 
               
               
                 Test duration, hrs 
                   
                 3500 
               
               
                   
               
               
                 Examples: PCT11(PC08-2/3): blind primary interconnect is via design FIG. 6 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 (with ceramic seal) 
               
            
           
           
               
               
               
            
               
                   
                 General Composition 
                 Specific Composition 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 Anode 
                 NiO—YSZ (NiO = 55-75 wt %) 
                   
               
               
                 Anode conductive layer 
                 Pd—Ni—YSZ 
               
               
                 Cathode 
                 La (1−x) Sr x MnO (3−δ) (x = 0.1-0.3) —3YSZ 
               
               
                 Cathode conductive layer 
                 Pd—La (1−x) Sr x MnO (3−δ)  (x = 0.1-0.3) 
               
               
                 Electrolyte 
                 3YSZ 
                 3YSZ 
               
               
                 Blind primary conductor 
                 Pd—Ni—YSZ 
                 76.5%Pd, 8.5%Ni, 15%3YSZ 
               
               
                 Auxiliary conductor on anode side 
                 Pd—Ni—YSZ 
                 76.5%Pd, 8.5%Ni, 15%3YSZ 
               
               
                 Auxiliary conductor on cathode side 
                 Pd—La (1−x) Sr x MnO (3−δ)  (x = 0.1-0.3) 
               
               
                 Substrate 
                 MgO—MgAl 2 O 4   
                 69.4%MgO, 30.6%MgAl 2 O 4   
               
               
                 Substrate surface modification layer 
                 3-8 mol %Y 2 O 3 —ZrO 2   
                 8YSZ 
               
               
                 Ceramic seal 
                 3-5 mol %Y 2 O 3 —ZrO 2 , or 
                 3YSZ 
               
               
                   
                 4-6 mol %Sc 2 O 3 —ZrO 2   
               
               
                 cell &amp; interconnect ASR, ohm-cm{circumflex over ( )}2 
                   
                   0.50 
               
               
                 Test duration, hrs 
                   
                 1200 
               
               
                   
               
               
                 Examples: TCT2: blind primary interconnect is long strip design FIG. 8 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 (Pd—NTZ as chemical barrier) 
               
            
           
           
               
               
               
            
               
                   
                 General Composition 
                 Specific Composition 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 Anode 
                 NiO—YSZ (NiO = 55-75 wt %) 
                   
               
               
                 Anode conductive layer 
                 Pd—NiO—(Mg 0.42 ,Ni 0.58 )Al 2 O 4   
               
               
                 Cathode 
                 La (1−x) Sr x MnO (3−δ) (x = 0.1-0.3) —3YSZ 
               
               
                 Cathode conductive layer 
                 La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3) 
               
               
                 Electrolyte 
                 3-8 mol %Y 2 O 3 —ZrO 2 , or 
                 3YSZ 
               
               
                   
                 4-11 mol %Sc 2 O 3 —ZrO 2   
               
               
                 Blind primary conductor 
                   x Pd(100 − x)Pt—YSZ (x = 35-65 wt ratio, 
                 31.1%Pd, 31.1%Pt, 24.4% 3YSZ 
               
               
                   
                 alloy is 35-80 v %) 
               
               
                 Chemical barrier on anode side 
                   x Pd—(100 − x) NTZ* (x = 10-40) 
                 15%Pd, 19%NiO, 66%NTZ 
               
               
                 Auxiliary conductor on 
                 La(1 − x)Sr x MnO(3 − d) (x = 0.1-0.3) 
               
               
                 cathode side 
               
               
                 Substrate 
                 MgO—MgAl 2 O 4   
                 69.4%MgO, 30.6%MgAl 2 O 4   
               
               
                 Substrate surface 
                 3-8 mol %Y 2 O 3 —ZrO 2   
                 8YSZ 
               
               
                 modification layer 
               
               
                 Ceramic seal 
                 N/A 
                 N/A 
               
               
                 Cell ASR, ohm-cm{circumflex over ( )}2 
                   
                   0.35 
               
               
                 Interconnect ASR, ohm-cm{circumflex over ( )}2 
                   
                 0.02-0.05 
               
               
                 Test duration, hrs 
                   
                 1400 
               
               
                   
               
               
                 *NTZ: 73.6 wt %NiO, 20.0%TiO 2 , 6.4% YSZ 
               
               
                 Examples: PCT14B (PC11-4), blind vias, FIG. 11 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 wt % (GDC10 as chemical barrier) 
               
            
           
           
               
               
               
            
               
                   
                 General Composition 
                 Specific Composition 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 Anode 
                 NiO—YSZ (NiO = 55-75 wt %) 
                   
               
               
                 Anode conductive layer 
                 Pd—NiO—(Mg 0.42 ,Ni 0.58 )Al 2 O 4   
               
               
                 Cathode 
                 La (1−x) Sr x MnO (3−δ) (x = 0.1-0.3) —3YSZ 
               
               
                 Cathode conductive layer 
                 La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3) 
               
               
                 Electrolyte 
                 3-8 mol %Y 2 O 3 —ZrO 2 , or 
                 3YSZ 
               
               
                   
                 4-11 mol %Sc 2 O 3 —ZrO 2   
               
               
                 Blind primary conductor 
                   x Pd—(100 − x)YSZ (x = 70-90 weight ratio) 
                 85%Pd, 15%3YSZ 
               
               
                 Chemical barrier on anode side 
                 Doped Ceria 
                 (Gd 0.1 ,Ce 0.9 )O 2   
               
               
                 Auxiliary conductor on 
                 La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3) 
               
               
                 cathode side 
               
               
                 Substrate 
                 MgO—MgAl 2 O 4   
                 69.4%MgO, 30.6%MgAl 2 O 4   
               
               
                 Substrate surface 
                 3-8 mol %Y 2 O 3 —ZrO 2   
                 8YSZ 
               
               
                 modification layer 
               
               
                 Ceramic seal 
                 3-5 mol %Y 2 O 3 —ZrO 2 , or 
                 3YSZ 
               
               
                   
                 4-6 mol %Sc 2 O 3 —ZrO 2   
               
               
                 Cell ASR, ohm-cm{circumflex over ( )}2 
                   
                   0.24 
               
               
                 Interconnect ASR, ohm-cm{circumflex over ( )}2 
                   
                 0.04-0.05 
               
               
                 Test duration, hrs 
                   
                 1340 
               
               
                   
               
               
                 Examples: PCT55A (PC28-2) for FIG. 12 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 wt % 
               
            
           
           
               
               
               
            
               
                   
                 General Composition 
                 Specific Composition 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 Anode 
                 NiO—YSZ (NiO = 55-75 wt %) 
                   
               
               
                 Anode conductive layer 
                 Pd—NiO—(Mg 0.42 ,Ni 0.58 )Al 2 O 4   
               
               
                 Cathode 
                 La (1−x) Sr x MnO (3−δ) (x = 0.1-0.3) —3YSZ 
               
               
                 Cathode conductive layer 
                 La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3), or 
               
               
                   
                 LaNi 0.6 Fe 0.4 O 3   
               
               
                 Electrolyte 
                 4-11 mol % Sc 2 O 3 —ZrO 2   
                 6ScSZ 
               
               
                 Blind primary conductor 
                   x Pd(100 − x)Pt—YSZ (x = 35-65 wt ratio, 
                 31.1%Pd, 31.1%Pt, 24.4% 3YSZ 
               
               
                   
                 alloy is 35-80 v %) 
               
               
                 Chemical barrier on anode side 
                 Doped Ceria 
                 (Gd 0.1 ,Ce 0.9 )O 2   
               
               
                 Auxiliary conductor on 
                 La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3), or 
               
               
                 cathode side 
                 LaNi 0.6 Fe 0.4 O 3   
               
               
                 Substrate 
                 MgO—MgAl 2 O 4   
                 69.4%MgO, 30.6%MgAl 2 O 4   
               
               
                 Substrate surface 
                 3-8 mol %Y 2 O 3 —ZrO 2   
                 8YSZ 
               
               
                 modification layer 
               
               
                 Ceramic seal 
                 3-5 mol %Y 2 O 3 —ZrO 2 , or 
                 3YSZ 
               
               
                   
                 4-6 mol %Sc 2 O 3 —ZrO 2   
               
               
                 Cell ASR, ohm-cm{circumflex over ( )}2 
                   
                   0.24 
               
               
                 Interconnect ASR, ohm-cm{circumflex over ( )}2 
                   
                 0.05-0.06 
               
               
                 Test duration, hrs 
                   
                 8000 
               
               
                   
               
               
                 Examples: PCT63A&amp;B For FIG. 16 
               
            
           
         
       
     
     
       
         
           
               
               
               
             
               
                   
                 TABLE 7 
               
               
                   
                   
               
               
                   
                 General Composition 
                 Specific Composition 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Anode 
                   
                   
               
               
                 Anode conductive layer 
               
               
                 Cathode 
               
               
                 Cathode conductive layer 
               
               
                 Electrolyte 
               
               
                 Blind primary conductor 
                 Pt—YSZ—SrZrO3 
                 78.8%Pt—11.1%3YSZ—10.1%SrZrO3 
               
               
                 Auxiliary conductor on anode side 
               
               
                 Auxiliary conductor on 
               
               
                 cathode side 
               
               
                 Substrate 
               
               
                 Substrate surface 
               
               
                 modification layer 
               
               
                 Ceramic seal 
               
               
                 Cell ASR, ohm-cm{circumflex over ( )}2 
               
               
                 Interconnect ASR, ohm-cm{circumflex over ( )}2 
               
               
                   
               
               
                 Examples: not tested in an actual SOFC test article, pellet formulation 
               
            
           
         
       
     
     Table 8 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 8 
               
               
                   
                   
               
               
                   
                 General Composition 
                 Specific Composition 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Anode 
                 NiO—YSZ (NiO = 55-75 wt %) 
                   
               
               
                 Anode conductive layer 
                 Pd—NiO—(Mg 0.42 ,Ni 0.58 )Al 2 O 4   
               
               
                 Cathode 
                 La (1−x) Sr x MnO (3−δ) (x = 0.1-0.3) —3YSZ 
               
               
                 Cathode conductive layer 
                 La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3) 
               
               
                 Electrolyte 
                 3-8 mol %Y 2 O 3 —ZrO 2   
                 3YSZ 
               
               
                 Blind primary conductor 
                 Pt—Pd—YSZ—La 2 O 3   
                 36%Pt—36%Pd—25.2%3YSZ—2.8%La 2 O 3   
               
               
                 Auxiliary conductor on anode side 
                 Pt—Pd—YSZ—La 2 O 3   
                 36%Pt—36%Pd—25.2%3YSZ—2.8%La 2 O 3   
               
               
                 Auxiliary conductor on 
                 La (1−x) Sr x MnO (3−d)  (x = 0.1-0.3) 
               
               
                 cathode side 
               
               
                 Substrate 
                 MgO—MgAl 2 O 4   
                 69.4%MgO, 30.6%MgAl 2 O 4   
               
               
                 Substrate surface 
                 3-8 mol %Y 2 O 3 —ZrO 2   
                 8YSZ 
               
               
                 modification layer 
               
               
                 Ceramic seal 
                 3-5 mol %Y 2 O 3 —ZrO 2 , or 
                 3YSZ 
               
               
                   
                 4-6 mol %Sc 2 O 3 —ZrO 2   
               
               
                 Cell ASR, ohm-cm{circumflex over ( )}2 
                   
                  0.3-0.34 
               
               
                 Interconnect ASR, ohm-cm{circumflex over ( )}2 
                   
                 0.04-0.07 
               
               
                   
               
               
                 Examples: PCT57 
               
            
           
         
       
     
     Embodiments of the present invention include a fuel cell system, comprising: a plurality of electrochemical cells, each electrochemical cell formed of an anode, a cathode spaced apart from the anode, and an electrolyte disposed between the anode and the cathode; an interconnect electrically coupling a pair of electrically adjacent electrochemical cells, the interconnect electrically coupling the anode of one electrochemical cell to the cathode of the other electrochemical cell; and a cathode conductive layer electrically coupled to the interconnect, wherein the interconnect is in contact with the cathode conductive layer and in contact with the electrolyte; and wherein the interconnect is formed of a cermet compound having a reactant phase configured for in-situ formation of at least one non-ionic conducting ceramic phase during firing of the fuel cell system. 
     In a refinement, the cermet compound include yttria stabilized zirconia (YSZ). 
     In another refinement, the reactant phase is SrO. 
     In yet another refinement, the reactant phase is configured to form a SrZrO 3  non-ionic conducting phase during the firing. 
     In still another refinement, the reactant phase is a rare earth oxide. 
     In yet still another refinement, the rare earth oxide is an oxide of at least one of La, Pr, Nd, Gd, Sm, Ho, Er and Yb. 
     In a further refinement, the reactant phase is configured to form a pyrochlore non-ionic conducting phase during the firing. 
     In a yet further refinement, the amount of the reactant phase is less than the stoichiometric ratio with the YSZ to form the non-ionic conducting phase. 
     In a still further refinement, the amount of the reactant phase is at the stoichiometric ratio with the YSZ to form the non-ionic conducting phase. 
     In a yet still further refinement, the amount of the reactant phase is greater than the stoichiometric ratio with the YSZ to form the non-ionic conducting phase. 
     In another further refinement, the cathode conductive layer is in contact with the electrolyte. 
     In yet another further refinement, the interconnect includes a portion embedded within the electrolyte. 
     Embodiments of the present invention include a fuel cell system, comprising: a cathode of a first electrochemical cell; an electrolyte; and an anode of a second electrochemical cell spaced apart from the cathode by the electrolyte; a cathode conductive layer adjoining the cathode; an interconnect configured to conduct free electrons between the anode and the cathode, wherein the interconnect adjoins both the cathode conductive layer and the electrolyte; and wherein the interconnect is formed of a cermet compound having a reactant phase configured for in-situ formation of at least one non-ionic conducting ceramic phase during firing of the fuel cell system. 
     In a refinement, the cermet compound include yttria stabilized zirconia (YSZ). 
     In another refinement, the reactant phase is SrO. 
     In yet another refinement, the reactant phase is configured to form a SrZrO 3  non-ionic conducting phase during the firing. 
     In a further refinement, the reactant phase is a rare earth oxide. 
     In a yet further refinement, the rare earth oxide is an oxide of at least one of La, Pr, Nd, Gd, Sm, Ho, Er and Yb. 
     In a still further refinement, the reactant phase is configured to form a pyrochlore non-ionic conducting phase during the firing. 
     In a yet still further refinement, the amount of the reactant phase is less than the stoichiometric ratio with the YSZ to form the non-ionic conducting phase. 
     In another further refinement, the amount of the reactant phase is at the stoichiometric ratio with the YSZ to form the non-ionic conducting phase. 
     In yet another further refinement, the amount of the reactant phase is greater than the stoichiometric ratio with the YSZ to form the non-ionic conducting phase. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.