Fuel cell matrix composition and method of manufacturing same
A composition for use in forming a fuel cell matrix includes a support material, an electrolyte material, and an additive material that includes a plurality of flakes having an average length in a range of 5 to 40 micrometers and an average thickness of less than 1 micrometer.
1. A green tape cast element for use in forming a fuel cell matrix, the green tape cast element being formed by tape casting a composition comprising:
a support material comprising lithium aluminum oxide,
an electrolyte material comprising one or more of carbonate electrolyte and carbonate electrolyte precursor, and
an additive material consisting essentially of aluminum flakes having an average length in a range of 5 μm to 40 μm and an average thickness of less than 1 μm.
2. The green tape cast element in accordance with claim 1 , wherein the flakes of the additive material have an average Brunauer-Emmett-Teller (BET) surface area from 1 m 2 /g to 6 m 2 /g.
3. The green tape cast element in accordance with claim 1 , wherein an amount of the additive material in the composition is between 3 volume percent and 35 volume percent.
4. The green tape cast element in accordance with claim 1 , wherein the flakes of the additive material have a leafing value of 70 to 100%.
5. The green tape cast element in accordance with claim 1 , wherein the plurality of flakes have an average length in a range of 12 μm to 20 μm.
6. The green tape cast element in accordance with claim 1 , wherein the plurality of flakes have an average length in a range of 15 μm to 18 μm.
7. The green tape cast element in accordance with claim 1 , wherein the plurality of flakes have an average thickness of less than 0.5 μm.
8. The green tape cast element in accordance with claim 1 , wherein the plurality of flakes have an average thickness in a range of 0.1 μm to 0.3 μm.
9. The green tape cast element in accordance with claim 1 , wherein the flakes are coated with an acidic compound adapted to prevent re-agglomeration.
10. The green tape cast element in accordance with claim 9 , wherein the acidic compound is stearic acid.
11. The green tape cast element in accordance with claim 1 , further comprising a binder and a plasticizer.
12. A conditioned fuel cell matrix formed by conditioning the green tape cast element of claim 1 such that the additive material reacts with the electrolyte material.
13. The conditioned fuel cell matrix of claim 12 , wherein the conditioning is performed by heating the green tape cast element at a temperature of at least 500° C. for at least two hours.
14. The conditioned fuel cell matrix of claim 12 , wherein the conditioning is performed by heating the green tape cast element at a temperature in range of 500 to 650° C. for a time in a range of 2 to 150 hours.
15. The conditioned fuel cell matrix of claim 12 , wherein the conditioned fuel cell matrix has a snap strength of at least 657 PSI.
16. A fuel cell system comprising one or more fuel cells, each of the fuel cells including an anode electrode, a cathode electrode and a conditioned fuel cell matrix in accordance with claim 12 .