SOFC stack having a high temperature bonded ceramic interconnect and method for making same

A method for forming an integrated solid oxide fuel cell (SOFC) stack comprising:

• forming a first cell structure, the first cell structure having a first electrode layer, an electrolyte layer overlying the first electrode layer, and a second electrode layer overlying the electrolyte layer;
• forming a ceramic interconnect layer overlying the first cell structure;
• forming a second cell structure, the second cell structure having a first electrode layer, an electrolyte layer overlying the first electrode layer, and a second electrode layer overlying the electrolyte layer;
• and
• hot pressing the first cell structure, the ceramic interconnect layer, and the second cell structure together during a single hot pressing cycle to integrally bond the first cell structure, the ceramic interconnect layer and the second cell structure to form an integrated SOFC stack,
• wherein the hot pressing is conducted at a temperature not less than 1200° C. and not greater than 1,800° C. and a pressure of not less than 0.5 MPa and not greater than 10 MPa,
• wherein the ceramic interconnect layer of the integrated SOFC stack is planar and has a thickness of not less than 1 micron and not greater than 15 microns,
• wherein the integrated SOFC stack includes a diffusion region along an interfacial region of the ceramic interconnect layer and the first cell structure, the second cell structure, or a combination thereof, and
• wherein the first cell structure and the second cell structure include gas delivery channels formed within the first electrode layer or the second electrode layer.

A method for forming an integrated, densified solid oxide fuel cell (SOFC) component comprising:

• forming a first green cell structure having a first green electrode layer, a green electrolyte layer overlaying the first green electrode layer, and a second green electrode layer overlaying the green electrolyte layer;
• forming a second green cell structure having a first green electrode layer, a green electrolyte layer overlaying the first green electrode layer, and a second green electrode layer overlaying the green electrolyte layer;
• forming a green ceramic interconnect layer disposed between the first green cell structure and the second green cell structure;
• and
• hot pressing the first green cell structure, the green ceramic interconnect layer, and the second green cell structure together during a single hot pressing cycle to integrally bond the first green cell structure, the green ceramic interconnect layer and the second green cell structure to form an integrated, densified SOFC component,
• forming gas delivery channels within a resultant first electrode layer or a resultant second electrode layer of a resultant first or second cell structure of the integrated, densified SOFC component;
• wherein a resultant interconnect layer of the integrated, densified SOFC component is planar and has a thickness of not less than 1 micron and not greater than 15 microns, and wherein the hot pressing is conducted at a temperature not less than 1200° C. and not greater than 1,800° C. and a pressure of not less than 0.5 MPa and not greater than 10 MPa.