Electrochemical apparatus and process
AssigneeTechnology Management, Inc.
InventorsThomas L. Cable, Michael A. Petrik
Life of this patent
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Abstract
The electrical performance of an electrochemical apparatus such as a fuel cell and the durability of the fuel cell elements can be significantly enhanced and extended by the addition of an element between at least one electrode (the oxygen electrode and/or the fuel electrode) and the electrolyte. Performance can be additionally enhanced by the design of at least one electrode to alter its flow characteristics. An integrated separator element can additionally function as at least one electrode of the fuel cell. The electrochemical apparatus is tolerant of the utilization of sulfur bearing fuels.
Claims41
An electrochemical apparatus having a solid electrolyte disposed between an oxygen electrode and a fuel electrode, at least one separator contacting the surface of one of the electrodes opposite the electrolyte, and a reactive microslip zone disposed between the electrolyte and at least one electrode, wherein the reactive microslip zone has interconnected pores of a lesser average diameter than the pores of the adjacent electrode, wherein the electrolyte has a fuel electrode material interfacial layer on the electrolyte surface proximate to the fuel electrode, and wherein at least one of the interfacial layer, the fuel electrode, and the reactive microslip zone comprises at least one sulfur tolerant material.
An electrochemical apparatus comprising a fuel cell having an electrolyte disposed between a fuel electrode and a second electrode, wherein a fuel electrode material interfacial layer is further disposed between the electrolyte and the fuel electrode, said interfacial layer comprising at least one sulfur tolerant material comprising a conductor selected from the classes consisting of electronic, ionic, mixed ionic/electronic and combinations thereof.
A solid electrolyte electrochemical apparatus having a solid electrolyte disposed between an oxygen electrode and a fuel electrode in a cell, and at least one separator contacting the surface of one of the electrodes opposite the electrolyte, wherein the electrolyte has a fuel electrode material interfacial layer on the electrolyte surface proximate to the fuel electrode and wherein at least one of the electrodes has enhanced, fixed interconnected porosity of greater than about 50% to about 90% to substantially eliminate gas backflow in the cell, said at least one electrode being contiguous to an electrical contact zone adjacent to the electrolyte, and wherein at least one of the fuel electrode and the interfacial layer comprise at least one sulfur tolerant material.
A solid electrolyte electrochemical apparatus having a solid electrolyte disposed between an oxygen electrode and a fuel electrode in a cell, and at least one separator contacting the surface of one of the electrodes opposite the electrolyte, wherein the electrolyte has a fuel electrode material interfacial layer on the electrolyte surface proximate to the fuel electrode and wherein at least one of the electrodes has enhanced, fixed interconnected porosity of greater than about 50% to about 90% to substantially eliminate gas backflow in the cell, said at least one enhanced porosity electrode being contiguous to an electrical contact zone adjacent to the electrolyte, and having a reactive microslip zone disposed between the electrolyte and said at least one enhanced porosity electrode, wherein the reactive microslip zone has interconnected pores of a lesser average diameter than the pores of the enhanced porosity electrode, and wherein at least one of the interfacial layer, the reactive microslip zone, and the fuel electrode comprises at least one sulfur tolerant material.
A process for utilizing a sulfur bearing fuel in an electrochemical apparatus including introducing a fuel containing at least about 2 ppm sulfur species, at reaction temperature, into a nonbonded solid oxide electrolyte fuel cell, and reacting said fuel.
A process for utilizing a sulfur bearing fuel in an electrochemical apparatus including:
- providing a fuel cell having an electrolyte disposed between a fuel electrode and a second electrode, wherein a fuel electrode material interfacial layer is further disposed between the electrolyte and the fuel electrode, and wherein at least one of the interfacial layer and the fuel electrode comprises at least one sulfur tolerant material;
- introducing a fuel containing at least about 2 ppm sulfur species, at reaction temperature, into said fuel cell;
- and,
- reacting said fuel.
An electrochemical apparatus comprising a fuel cell having an electrolyte disposed between a fuel electrode and a second electrode, wherein a fuel electrode material interfacial layer is further disposed between the electrolyte and the fuel electrode, and wherein at least one of the interfacial layer and the fuel electrode comprises at least one sulfur tolerant material.
An electrochemical apparatus comprising a fuel cell having an electrolyte disposed between a fuel electrode and a second electrode, wherein a fuel electrode material interfacial layer is further disposed between the electrolyte and the fuel electrode, and wherein at least one of the interfacial layer and fuel electrode comprises at least one sulfur tolerant conductor selected from:
- (I) Ag, Co, Cr, Cu, Fe, Ni, Pd, Pt, Ru, and alloys and mixtures thereof;
- (II) Oxides of the general formula M.sub.y M'.sub.1-y O.sub.x, wherein at least one M element is different than at least one M' element, wherein M is selected from Ba, Nb, Sr, and mixtures thereof, M' is selected from Ti, Sm, Nb and mixtures thereof, and wherein 0.ltoreq.y.ltoreq.1 and x is a number sufficient to satisfy the valence requirements of the other elements;
- (III) Perovskites of the general formula (A.sub.1-a A'.sub.a)(B.sub.b B'.sub.1-b)O.sub.3-c, wherein A is selected from lanthanides, La, Y, Nb, Ta, Pb and mixtures thereof, A' is selected from alkaline earth metals such as Ba, Ca, Mg, Sr and mixtures thereof, B is selected from lanthanides and mixtures thereof, and B' is selected from Al, Cr, Nb, Ti, Zr and mixtures thereof,
- wherein 0.9.ltoreq.(A+A')/(B+B').ltoreq.1.1, preferably 0.99.ltoreq.(A+A')/(B+B').ltoreq.1.01;
- and wherein 0.ltoreq.a.ltoreq.1;
- 0.ltoreq.b.ltoreq.1;
- and c is a number that renders the composition charge neutral in the absence of an applied potential;
- (IV) Oxides of the general formula Me.sub.z Me'.sub.1-z O.sub.x, wherein at least one Me element is different than at least one Me' element, wherein Me is selected from Group 2a and 3a (IUPAC) metals, lanthanides, Cr, Fe, In, Nb, Pb, Sn, Ta, Ti, and mixtures thereof, Me' is selected from Bi, Ce, In, Th, U, Zr and mixtures thereof, and wherein 0.ltoreq.z.ltoreq.1 and x is a number sufficient to satisfy the valence requirements of the other elements;
- (V) Perovskites of the general formula (D.sub.1-d D'.sub.d)(E.sub.e E'.sub.1-e)O.sub.3-f, wherein D is selected from lanthanides, La, Y, Nb, Ta, and mixtures thereof, D' is selected from alkaline earth metals such as Ba, Ca, Mg, Sr and mixtures thereof, E is selected from lanthanides and mixtures thereof, and E' is selected from Co, Cr, Cu, Fe, Ni, Zr and mixtures thereof,
- wherein 0.9.ltoreq.(D+D')/(E+E').ltoreq.1.1, preferably 0.99.ltoreq.(D+D')/(E+E').ltoreq.1.01;
- and wherein 0.ltoreq.d.ltoreq.1;
- 0.ltoreq.e.ltoreq.1;
- and f is a number that renders the composition charge neutral in the absence of an applied potential.
Dependencies are inferred from the claim text.