Proton conductive electrolyte and fuel cell comprising the same

Abstract

Aspects of the present invention provide a proton conductive electrolyte suitable for a fuel cell material and a fuel cell including the proton conductive electrolyte. More particularly, aspects of the present invention provide a proton conductive electrolyte that has good proton conductivity and can be used to form a membrane having good flexibility. As a result, the proton conductive electrolyte can be used in a fuel cell, the electrolyte membrane of a fuel cell or the electrodes thereof, and can provide a solid polymer fuel cell having high current density, high power and long life-time in a dry environment (relative humidity of 50% or less) at an operating temperature of 100 to 200° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic cross-sectional view of a unit cell of a fuel cell employing a proton conductive electrolyte according to an embodiment of the present invention; and

FIGS. 2 and 3 are graphs illustrating the temperature dependence of the proton conductivity of proton conductive electrolytes according to exemplary embodiments of the present invention.

Claims

1. A proton conductive electrolyte comprising a polyamidic acid derivative: wherein a carboxyl group or a sulfamic acid group is incorporated as a side chain in the polyamide; and,wherein an alkyl group is incorporated in the main chain.

2. The proton conductive electrolyte of claim 1, wherein the polyamidic acid derivative is represented by Formula 1 below:

3. The proton conductive electrolyte of claim 2, wherein R of the polyamidic acid derivative of Formula 1 is a C3-C12 alkyl group.

4. The proton conductive electrolyte of claim 1, wherein the polyamidic acid derivative is a compound in which the carboxyl group is completely or partially amidosulfonated.

5. The proton conductive electrolyte of claim 4, wherein the polyamidic acid derivative is obtained by completely or partially reacting the carboxylic acid group with carbonyl chloride, reacting the resultant with amidosulfonate triethylamine salts, and then cation exchanging the resulting product.

6. A fuel cell comprising an oxygen electrode, a fuel electrode, an electrolyte membrane interposed between the oxygen electrode and the fuel electrode wherein each electrolyte membrane comprises a proton conductive electrolyte according to claim 1, an oxidizing agent bipolar plate having oxidizing agent flow paths wherein the oxidizing agent flow paths are disposed on the external surface of the oxygen electrode, and a fuel bipolar plate having flow paths wherein the fuel paths are disposed on the external surface of the fuel electrode.

7. The fuel cell of claim 6, wherein the proton conductive electrolyte according to claim 1 is also incorporated in the oxygen electrode and the fuel electrode.

8. A proton conductive electrolyte comprising a polyvinyl sulfamic acid copolymer represented by Formula 2 below:

9. A fuel cell comprising an oxygen electrode, a fuel electrode, an electrolyte membrane interposed between the oxygen electrode and the fuel electrode wherein the electrolyte membrane comprises a proton conductive electrolyte according to claim 8, an oxidizing agent bipolar plate having oxidizing agent flow pathes wherein the oxidizing agent flow paths are disposed on the external surface of the oxygen electrode, and a fuel bipolar plate having fuel paths wherein the fuel paths are disposed on the surface of the fuel electrode.

10. The fuel cell of claim 9, wherein the proton conductive electrolyte according to claim 8 is also incorporated in the oxygen electrode and the fuel electrode.

11. A proton conductive electrolyte according to claim 1, wherein the polyamidic acid derivative is mixed with a polyvinyl sulfamic acid copolymer represented by the formula:

12. The proton conductive electrolyte of claim 11, wherein the mixing ratio of polyamidic acid derivatives and polyvinyl sulfamic acid copolymer is a mass ratio and is in the range of 9/1-1/1.

13. A fuel cell comprising an oxygen electrode and a fuel electrode an electrolyte membrane interposed between the oxygen electrode and the fuel electrode wherein the electrolyte membrane comprises a proton conductive electrolyte according to claim 11, an oxidizing agent bipolar plate having oxidizing agent flow paths wherein the oxidizing agent flow paths are disposed on the external surface of the oxygen electrode; and a fuel bipolar plate having fuel paths wherein the fuel paths are disposed on the external surface of the fuel electrode.

14. The fuel cell of claim 13, wherein the proton conductive electrolyte according to claim 13 is also incorporated in the oxygen electrode and the fuel electrode.

15. A proton conductive electrolyte comprising one or more polymers: wherein a sulfamic acid group is incorporated as a substituent of the polymers; andwherein the elements incorporated into the polymers comprise one or more elements taken from the group consisting of carbon, hydrogen, oxygen, nitrogen, sulfur, chlorine, bromine and iodine.

16. The proton conductive electrolyte of claim 15, comprising an alkyl chain polymer wherein the sulfamic acid group is incorporated as a side chain in the polymer.

17. The proton conductive electrolyte of claim 8, wherein the average polymerization ratio (n/m) of the polyvinyl sulfamic acid copolymer is 3/7 to 7/3.

18. The proton conductive electrolyte of claim 1, further comprising a polytetrafluoroethylene polymer.

19. The proton conductive electrolyte of claim 1, further comprising a basic polymer wherein the basic polymer is taken from the group consisting of nitrogen-containing polymers, oxygen containing polymers, and sulfur-containing polymers.

20. The proton conductive electrolyte of claim 1, further comprising a phosphate containing compound wherein the phosphate containing compound consists of compounds taken from the group of orthophosphates, metaphosphates, and polyphosphates.

21. The fuel cell of claim 6, wherein the fuel electrode and the oxygen electrode further comprise a porous catalyzing layer; wherein the fuel electrode and the oxygen electrode further comprise a porous carbon sheet supporting the porous catalyzing layer; andwherein the porous catalyzing layer further incorporates an electrode catalyst, a hydrophobic binder, and a conducting agent.

22. The fuel cell of claim 9, wherein the fuel electrode and the oxygen electrode further comprise a porous catalyzing layer; wherein the fuel electrode and the oxygen electrode further comprise a porous carbon sheet supporting the porous catalyzing layer; andwherein the porous catalyzing layer further incorporates an electrode catalyst, a hydrophobic binder, and a conducting agent.

23. The fuel cell of claim 13, wherein the fuel electrode and the oxygen electrode further comprise a porous catalyzing layer; wherein the fuel electrode and the oxygen electrode further comprise a porous carbon sheet supporting the porous catalyzing layer; andwherein the porous catalyzing layer further incorporates an electrode catalyst, a hydrophobic binder, and a conducting agent.