Matrix material for the gas diffusion layer of the polymer electrolyte membrane fuel cell

Abstract

The invention provides a matrix material for the gas diffusion layer of the polymer electrolyte membrane fuel cell, which is composed of three-dimensional porous and strip-shaped hexagonal chambers connected to each other, wherein the six-sided ribs are composed of two metal layers, the inside is metal nickel, and the outside is tungsten-nickel alloy. The total mass of metal per square meter of the material is: 1500˜3000 grams, the mass content of metal nickel in the material is 88˜92%, the mass content of metal tungsten is 8˜12%, and the rest are impurities; the thickness of the matrix material is 0.1˜0.2 mm, specific surface area is (1˜2)×10.sup.5 m.sup.2/m.sup.3; longitudinal air permeability ≥2000 m/mm/(cm.sup.2hmmAq), longitudinal thermal conductivity ≥1.7W/(m.Math.k), transverse thermal conductivity ≥21W/(m.Math.K). The porous nickel-tungsten metal material of the invention, as the matrix material of the gas diffusion layer, has the advantages of lower electrical resistance and higher strength compared with carbon paper.

Claims

1. A matrix material for the gas diffusion layer of the polymer electrolyte membrane fuel cell, the matrix material is composed of three-dimensional porous and strip-shaped hexagonal chambers connected to each other, wherein the six-sided ribs are composed of two metal layers, the inside is metal nickel, and the outside is tungsten-nickel alloy. The total mass of metal per square meter of the material is: 1500˜3000 grams, the mass content of metal nickel in the material is 88˜92%, the mass content of metal tungsten is 8˜12%, and the rest are impurities; the thickness of the matrix material is 0.1˜0.2 mm, specific surface area is (1˜2)×105 m2/m3; 0<material longitudinal resistivity ≤55 mΩ.Math.cm, 0<material sheet resistivity ≤4 mΩ.Math.cm, 0<material contact resistance ≤5 mΩ.Math.cm; material tensile strength is ≥25 Mpa.

2. The matrix material of claim 1, wherein the longitudinal air permeability of the material ≥2000 m/mm/(cm2hmmAq), and the longitudinal thermal conductivity is ≥1.7 W/(m.Math.k), transverse thermal conductivity is ≥21W/(m.Math.k).

3. The matrix material of claim 1, wherein the material as the positive electrode, the calomel electrode as the negative electrode, the sodium chloride aqueous solution as the electrolyte, with an applied potential of 1.45V for 75h, the weight loss rate of the material is ≤5%.

4. The matrix material of claim 1, wherein after the material being soaked in 4% H2O2 for 160h and then dried to reach a constant weight, the weight loss rate is ≤5%.

5. The matrix material of claim 3, wherein, after the material being soaked in 4% H2O2 for 160h and then dried to reach a constant weight, the weight loss rate is ≤5%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 SEM image of material in embodiment 2

DETAILED DESCRIPTION

Embodiment 1

(2) Firstly, a porous nickel strip with a thickness of 1.0 mm and 2650 grams of metal nickel per square meter is rolled to 0.5 mm, and then placed in a Watt nickel electroplating solution, with the porous nickel strip as the anode and nickel metal as the cathode, being electrolysis treated for 35 minutes, wherein the temperature of the electroplating nickel solution is 30° C., and the electroplating current density is 30 A/m.sup.2; then the electrolysis-treated porous nickel strip is heat-treated in an environment of 800˜1000° C. with a reducing atmosphere for a certain period of time. The time is based on 15 minutes per square meter of material processing. After heat treatment, the porous nickel strip is placed in the following composite tungsten electroplating solution for 15 minutes; and then heat treated in a 900° C. environment with a reducing atmosphere for a certain period of time, the time is based on 40 minutes per square meter of material processing; finally, the heat-treated porous nickel-tungsten metal strip is rolled to 0.1 mm. The composite tungsten electroplating solution used above is the concentration of sodium tungstate is 80 g/L, the concentration of triamine citrate is 30 g/L, the concentration of nickel sulfate is 50 g/L, the pH value of the tungsten electroplating solution is controlled as 6.5, the temperature is 55° C. and the electroplating current density is 25 A/dm.sup.2.

Embodiment 2

(3) A matrix material for the gas diffusion layer of a polymer electrolyte membrane fuel cell was prepared by the method of Embodiment 1. The scanning electron microscope is shown in FIG. 1. The matrix material is composed of three-dimensional porous and strip-shaped hexagonal chambers 1 connected to each other, wherein the six-sided ribs 2 are composed of two metal layers, the inside is metal nickel, and the outside is tungsten-nickel alloy. The total mass of metal per square meter of material is 1670 grams, the mass content of metal nickel in the material is 89%, the mass content of metal tungsten is 10.5%, and the rest are impurities; the thickness of the matrix material is 0.1 mm, and the specific surface area is 1.5×10.sup.5 m.sup.2/m.sup.3; the porosity of the material is 82%, longitudinal air permeability is 2300 m/mm/(cm.sup.2hmmAq), longitudinal resistivity is 30 mΩ.Math.cm, sheet resistivity is 2.1 mΩ.Math.cm, contact resistivity is 3 mΩ.Math.cm; the tensile strength of the material is 75 Mpa; the longitudinal thermal conductivity of the material is 1.95 W/(m.Math.k), and the transverse thermal conductivity is 23 W/(m.Math.k). The above material is used as the positive electrode, the calomel electrode is used as the negative electrode, the sodium chloride aqueous solution is used as the electrolyte, and the applied potential of 1.45V is used for 75h, and the weight loss rate of the material is 3.5%. After the material is soaked in 4% H.sub.2O.sub.2 for 160 hours and then dried to reach a constant weight, the weight loss rate of the material is 3.85%.

Embodiment 3

(4) Firstly, a porous nickel strip with a thickness of 1.0 mm and 2400 grams of metal nickel per square meter is rolled to 0.5 mm, and then placed in a Watt nickel electroplating solution, with the porous nickel strip as the anode and nickel metal as the cathode, Electrolytic treatment is carried out for 45 minutes, wherein the temperature of the electroplating nickel solution is 30° C., and the electroplating current density is 25 A/dm.sup.2; after that, the porous nickel strip is heat-treated in an environment of 800° C. with a reducing atmosphere for a certain period of time. The time is based on 55 minutes per square meter of material. The heat-treated porous nickel strip is placed in the following electroplating tungsten bath for 10 minutes; then heat-treated for a certain period of time in a 1000° C. environment with a reducing atmosphere, the time is based on 10 minutes per square meter of material; finally, the heat-treated porous nickel-tungsten metal strip is rolled to 0.1 mm. The tungsten electroplating solution used above is the concentration of sodium tungstate is 80 g/L, the concentration of triamine citrate is 30 g/L, the pH value of the tungsten electroplating solution is controlled as 6.5, the temperature is 55° C., and the electroplating current density is 20 A/dm.sup.2.

Embodiment 4

(5) A matrix material for the gas diffusion layer of polymer electrolyte membrane fuel cell was prepared by embodiment 3, the scanning electron microscope is shown in FIG. 1. The matrix material is composed of three-dimensional porous and strip-shaped hexagonal chambers 1 connected to each other, wherein the six-sided ribs 2 are composed of two metal layers, the inside is metal nickel, and the outside is tungsten-nickel alloy. The total mass of metal per square meter of material is: 2270 grams, the mass content of metal nickel in the material is 91%, the mass content of metal tungsten is 8.9%, and the rest are impurities; the thickness of the matrix material is 0.2 mm, and the specific surface area is 1.87×10.sup.5 m.sup.2/m.sup.3; porosity of the material is 85%, longitudinal air permeability is 2480 m/mm/(cm.sup.2hmmAq), longitudinal resistivity is 36 mΩ.Math.cm, sheet resistivity is 31 mΩ.Math.cm, contact resistivity is 3.6 mΩ.Math.cm, the tensile strength of the material is 65 Mpa; the longitudinal thermal conductivity of the material is 2.1 W/(m.Math.k), and the transverse thermal conductivity is 25 W/(m.Math.k). The above-mentioned material is used as the positive electrode, the calomel electrode is used as the negative electrode, and the sodium chloride aqueous solution is used as the electrolyte. The applied potential of 1.45V is used for 75h, and the weight loss rate of the material is 4%. After the material was soaked in 4% H.sub.2O.sub.2 for 160 hours and then dried to reach a constant weight, the weight loss rate of the material is 3.2%.