High-performance electrolyte for molten carbonate fuel cell

1. A molten carbonate fuel cell assembly comprising:

a cathode electrode;

an anode electrode;

an electrolyte matrix disposed between the cathode electrode and the anode electrode;

a cathode current collector abutting the cathode electrode; and

a first electrolyte composition stored in the cathode electrode, the first electrolyte composition comprising a first mixture of a eutectic Li/Na carbonate electrolyte doped with one or more additive materials, wherein the one or more additive materials comprise a combination of SrO and BaCO 3 or a combination of SrCO 3 and BaCO 3 ;

wherein:

the eutectic Li/Na carbonate electrolyte comprises 50 mol % to 54 mol % Li 2 CO 3 and 46 mol % to 50 mol % Na 2 CO 3 ; and

the first mixture comprises:

(a) 42 mol % to 48 mol % of Li 2 CO 3 , 38 mol % to 43 mol % of Na 2 CO 3 , 7 mol % to 13 mol % of SrO and 1 mol % to 7 mol % of BaCO 3 ; or

(b) 42 mol % to 48 mol % of Li 2 CO 3 , 38 mol % to 43 mol % of Na 2 CO 3 , 2 mol % to 8 mol % of SrCO 3 and 1 mol % to 5 mol % of BaCO 3 .

2. The molten carbonate fuel cell assembly in accordance with claim 1 , wherein the first electrolyte composition comprises at least 92 wt % of the first mixture.

3. The molten carbonate fuel cell assembly in accordance with claim 1 , further comprising a second electrolyte composition stored in at least the cathode current collector, the second electrolyte composition comprising an off-eutectic second mixture of Li 2 CO 3 and Na 2 CO 3 .

4. The molten carbonate fuel cell assembly in accordance with claim 3 , wherein the second mixture comprises 80 mol % or more of Li 2 CO 3 and 20 mol % or less of Na 2 CO 3 .

5. The molten carbonate fuel cell assembly in accordance with claim 4 , wherein the second mixture comprises 87 mol % to 90 mol % of Li 2 CO 3 and 10 mol % to 13 mol % of Na 2 CO 3 .

6. The molten carbonate fuel cell assembly in accordance with claim 1 , wherein the cathode current collector does not store therein any electrolyte doped with the one or more additive materials.

7. An electrolyte composition for a cathode electrode of a molten carbonate fuel cell, the electrolyte composition comprising:

a mixture of eutectic Li/Na carbonate electrolyte doped with one or more additive materials, wherein the one or more additive materials comprise a combination of SrO and BaCO 3 or a combination of SrCO 3 and BaCO 3 ;

wherein:

the eutectic Li/Na carbonate electrolyte comprises 50 mol % to 54 mol % Li 2 CO 3 and 46 mol % to 50 mol % Na 2 CO 3 ; and

the mixture comprises:

(a) 42 mol % to 48 mol % of Li 2 CO 3 , 38 mol % to 43 mol % of Na 2 CO 3 , 7 mol % to 13 mol % of SrO and 1 mol % to 7 mol % of BaCO 3 ; or

(b) 42 mol % to 48 mol % of Li 2 CO 3 , 38 mol % to 43 mol % of Na 2 CO 3 , 2 mol % to 8 mol % of SrCO 3 and 1 mol % to 5 mol % of BaCO 3 .

8. A method of manufacturing a molten carbonate fuel cell assembly, the method comprising:

providing a molten carbonate fuel cell assembly comprising a cathode electrode, an anode electrode, an electrolyte matrix, and a cathode current collector abutting the cathode electrode;

forming a first electrolyte composition comprising a first mixture of a first predetermined amount of eutectic Li/Na electrolyte composition doped with a second predetermined amount of one or more additive materials, wherein the one or more additive materials comprise a combination of SrO and BaCO 3 or a combination of SrCO 3 and BaCO 3 ; and

storing the first electrolyte composition in at least the cathode electrode of the molten carbonate fuel cell assembly;

wherein:

the eutectic Li/Na carbonate electrolyte comprises 50 mol % to 54 mol % Li 2 CO 3 and 46 mol % to 50 mol % Na 2 CO 3 ; and

the first mixture comprises 80 mol % to 92 mol % of the eutectic Li/Na carbonate electrolyte and 8 mol % to 20 mol % of the one or more additive materials.

9. A method of manufacturing a molten carbonate fuel cell assembly in accordance with claim 8 , further comprising:

forming a second electrolyte composition that is different form the first electrolyte composition; and

storing the second electrolyte composition in at least the cathode current collector.

10. A method of manufacturing a molten carbonate fuel cell assembly in accordance with claim 9 , wherein the second electrolyte composition comprises an off-eutectic second mixture of Li 2 CO 3 and Na 2 CO 3 comprising 80 mol % or more of Li 2 CO 3 and 20 mol % or less of Na 2 CO 3 .