Fuel cell matrix composition and method of manufacturing same

Abstract

A fuel cell matrix for use in a molten carbonate fuel cell comprising a support material and an additive material formed into a porous body, and an electrolyte material disposed in pores of the porous body, wherein the additive material is in a shape of a flake and has an average thickness of less than 1 μm.

We claim: 
     
         1 . A fuel cell matrix for use in a molten carbonate fuel cell comprising a support material and an additive material formed into a porous body, and an electrolyte material disposed in pores of the porous body, wherein the additive material is in a shape of a flake and has an average thickness of less than 1 μm. 
     
     
         2 . A fuel cell matrix in accordance with  claim 1 , wherein the additive material has one or more of:
 an average length from 5 μm to 40 μm   an average Brunauer-Emmett-Teller (BET) surface area from 1 m 2 /g to 6 m 2 /g and   a leafing value of 70 to 100%.   
     
     
         3 . A fuel cell matrix in accordance with  claim 1 , wherein the additive material is a metal additive material. 
     
     
         4 . A fuel cell matrix in accordance with  claim 3 , wherein the additive material comprises aluminum flake. 
     
     
         5 . A fuel cell matrix in accordance with  claim 4 , wherein the amount of additive material in the matrix is between 3 volume percent and 35 volume percent. 
     
     
         6 . A fuel cell matrix in accordance with  claim 5 , wherein:
 the support material comprises lithium aluminum oxide;   the additive material comprises aluminum; and   the electrolyte material comprises one or more of carbonate electrolyte and carbonate electrolyte precursor.   
     
     
         7 . A fuel cell system comprising one or more fuel cells, each of the fuel cells including an anode electrode, a cathode electrode and a fuel cell matrix in accordance with  claim 1 . 
     
     
         8 . A method of making a fuel cell matrix for use in a molten carbonate fuel cell, comprising:
 providing a first predetermined amount of a support material, a second predetermined amount of an electrolyte material and a third predetermined amount of an additive material;   processing said support material, electrolyte material and additive material to form the fuel cell matrix including a porous body formed from the support material and the additive material and the electrolyte material disposed in pores of the porous body,   wherein the additive material is in a shape of a flake and has an average thickness of less than 1 μm.   
     
     
         9 . A method of making a fuel cell matrix in accordance with  claim 8 , wherein the additive material has one or more of:
 an average length from 5 μm to 40 μm,   an average Brunauer-Emmett-Teller (BET) surface area from 1 m 2 /g to 6 m 2 /g and   a leafing value of 70 to 100%.   
     
     
         10 . A method of making a fuel cell matrix in accordance with  claim 8 , wherein the additive material is a metal additive material comprising aluminum. 
     
     
         11 . A method of making a fuel cell matrix in accordance with  claim 10 , wherein:
 the support material comprises lithium aluminum oxide;   the additive material comprises aluminum; and   the electrolyte material comprises one or more of carbonate electrolyte and carbonate electrolyte precursor.   
     
     
         12 . A method of making a fuel cell matrix in accordance with  claim 8 , wherein said processing step comprises:
 mixing the first predetermined amount of support material and the second predetermined amount of the electrolyte material to form a first mixture; and   adding the third predetermined amount of the additive material to the first mixture to form a second mixture.   
     
     
         13 . A method of making a fuel cell matrix in accordance with  claim 12 , wherein the processing step further comprises adding at least one of a binder and a plasticizer to the second mixture to form a third mixture, and forming the fuel cell matrix from said third mixture. 
     
     
         14 . A method of making a fuel cell matrix in accordance with  claim 13 , wherein said at least one of the binder and the plasticizer comprise about 19 to 20 weight percent of the fuel cell matrix. 
     
     
         15 . A method of making a fuel cell matrix in accordance with  claim 13 , wherein the forming the fuel cell matrix comprises casting the third mixture and then drying the cast mixture to form a tape element. 
     
     
         16 . A method of making a fuel cell matrix in accordance with  claim 12 , further comprising pre-milling the additive material prior to adding the additive material to the first mixture. 
     
     
         17 . A method of making a fuel cell matrix in accordance with  claim 16 , wherein the pre-milling of the additive material comprises milling the additive material for 100 to 300 minutes using grinding media having a size of 0.3 mm to 0.6 mm at a speed of 2,000 to 3,000 revolutions per minute. 
     
     
         18 . A method of making a fuel cell matrix in accordance with  claim 8 , wherein the third predetermined amount of additive material is 5 volume percent to 35 volume percent of the fuel cell matrix. 
     
     
         19 . A method of making a fuel cell matrix in accordance with  claim 18 , wherein the second predetermined amount of electrolyte material is between 5 and 100 volume percent of the first predetermined amount of support material. 
     
     
         20 . A method of making a fuel cell matrix in accordance with  claim 12 , wherein the mixing of the support material and the electrolyte precursor material to form the first mixture comprises milling at a speed of 2,000 to 3,000 revolutions per minute using a grinding media having a ball size of 0.3 to 3 mm at a loading of 60 to 80%. 
     
     
         21 . A method of making a fuel cell matrix in accordance with  claim 20 , wherein the mixing of the support material and the electrolyte material to form the first mixture is performed in a solvent comprising 1 volume percent to 6 volume percent of fish oil to prevent re-agglomeration of the support material and the electrolyte material. 
     
     
         22 . A method of making a fuel cell matrix for use in a molten carbonate fuel cell, comprising:
 providing a first predetermined amount of a support material, a second predetermined amount of an electrolyte material and a third predetermined amount of an additive particle material,   processing a mixture of the support material, the electrolyte material and the additive particle material to convert the additive particle material into an additive flake material having a shape of a flake and an average thickness of less than 1 μm and to form the fuel cell matrix including a porous body formed from the support material and the additive flake material and the electrolyte material disposed in the pores of the porous body.   
     
     
         23 . A method of making a fuel cell matrix in accordance with  claim 22 , wherein the additive flake material has one or more of:
 an average length from 5 μm to 40 μm,   an average Brunauer-Emmett-Teller (BET) surface area from 1 m 2 /g to 6 m 2 /g, and   a leafing value of 70 to 100%.   
     
     
         24 . A method of making a fuel cell matrix in accordance with  claim 23 , wherein the additive particle material is a metal particle material comprising aluminum. 
     
     
         25 . A method of making a fuel cell matrix in accordance with  claim 24 , wherein:
 the support material comprises lithium aluminum oxide;   the additive particle material comprises aluminum; and   the electrolyte material comprises one or more of carbonate electrolyte and carbonate electrolyte precursor.   
     
     
         26 . A method of making a fuel cell matrix in accordance with  claim 22 , wherein the processing step comprises:
 mixing the support material and the electrolyte material to form a first mixture;   adding the additive particle material to the first mixture to form a second mixture; and   milling the second mixture until the additive particle material is converted to the additive flake material.   
     
     
         27 . A method of making a fuel cell matrix in accordance with  claim 26 , wherein the processing step further comprises adding at least one of a binder and a plasticizer to the second mixture to form a third mixture and forming the fuel cell matrix from the third mixture. 
     
     
         28 . A method of making a fuel cell matrix in accordance with  claim 26 , wherein milling the second mixture comprises milling for 100 to 300 minutes using grinding media having a size of 0.3 mm to 0.6 mm at a speed of 2,000 to 3,000 revolutions per minute. 
     
     
         29 . A method of making a fuel cell matrix in accordance with  claim 22 , wherein the third predetermined amount of additive particle material is 5 volume percent to 35 volume percent of the fuel cell matrix. 
     
     
         30 . A method of making a fuel cell matrix in accordance with  claim 26 , wherein mixing the support material and the electrolyte material to form a first mixture comprises milling at a speed of 2,000 to 3,000 revolutions per minute using a grinding media having a ball size of 0.3 to 3 mm at a loading of 60 to 80%.