DURABLE IONOMERIC POLYMER FOR PROTON EXCHANGE MEMBRANE AND MEMBRANE ELECTRODE ASSEMBLIES FOR ELECTROCHEMICAL FUEL CELL APPLICATIONS
The present invention provides a proton exchange membrane and a membrane electrode assembly for an electrochemical fuel cell. A catalytically active component is disposed within the membrane electrode assembly. The catalytically active component comprises particles of cobalt cations and boron stabilized silicon oxide. The present invention also provides for a process for increasing peroxide radical resistance in a membrane electrode that includes the introduction of the catalytically active component described into a membrane electrode assembly.
1 . An electrochemical fuel cell membrane electrode assembly comprising:
an anode;
a cathode;
an ionomer membrane disposed between said anode and cathode; and
a catalytically active component disposed within the ionomer membrane, said catalytically active component comprising particles of cobalt cations and boron stabilized silicon oxide.
2 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said cobalt cations are comprised of Co 2+ and Co 3+ cations.
3 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said catalytically active component is additionally located in the electrode.
4 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said ionomer membrane comprises a polymer having an equivalent weight of up to 1000.
5 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said ionomer membrane comprises a polymer having an equivalent weight of up to 900.
6 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said ionomer membrane comprises a polymer having an equivalent weight of up to 800.
7 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said ionomer membrane is a reinforced membrane.
8 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said ionomer membrane is a dense membrane.
9 . The electrochemical fuel cell membrane electrode assembly of claim 8 , wherein said dense membrane is an extruded membrane.
10 . The electrochemical fuel cell membrane electrode assembly of claim 8 , wherein said dense membrane is a solvent cast membrane.
11 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said particles are colloidal particles having a mean particle diameter of less than 200 nanometers.
12 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said particles are colloidal particles having a mean particle diameter of less than 100 nanometers.
13 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said particles are colloidal particles having a mean particle diameter of less than 25 nanometers.
14 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said ionomer is a hydrocarbon ionomer.
15 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said ionomer is a partially fluorinated ionomer.
16 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said ionomer is a highly fluorinated ionomer.
17 . The electrochemical fuel cell membrane electrode assembly of claim 1 , wherein said ionomer is a perfluorinated sulfonic acid ionomer.
18 . The electrochemical fuel cell membrane electrode assembly of claim 11 , wherein said colloidal particles are additionally contained within the anode or cathode.
19 . The electrochemical fuel cell membrane electrode assembly of claim 11 , wherein said colloidal particles are present in a layer.
20 . A process for increasing the hydrogen peroxide radical resistance in an electrochemical fuel cell membrane electrode assembly comprising an anode, a cathode, an ionomer membrane disposed between said anode and cathode, comprising the step of:
introducing a catalytically active component within said ionomer membrane, said catalytically active component comprising cobalt cations and boron stabilized silicon oxide.
21 . The process of claim 20 , wherein the step of introducing a catalytically active component comprises imbibing said ionomer membrane with a solution of the catalytically active component in a solvent.
22 . The process of claim 20 , wherein the step of introducing a catalytically active component comprises solution casting the ionomer membrane from a mixture of an ionomer, a solvent, and said catalytically active component.
23 . A process for operating an electrochemical fuel cell membrane electrode assembly so as to increase resistance to peroxide radical attack, comprising the steps of:
(a) providing an ionomer membrane comprised of an ion-exchange polymer, said ionomer membrane having opposite first and second sides;
(b) forming an anode electrode adjacent to the first side of said ionomer membrane;
(c) forming a cathode electrode adjacent to the second side of said ionomer membrane;
(d) introducing a catalytically active component within said ionomer membrane, said catalytically active component comprising particles of cobalt cations and boron stabilized silicon oxide;
(e) forming an electric circuit between said anode and cathode electrodes; and
(f) providing a fuel to said anode electrode and oxygen to said cathode electrode so as to generate an electric current in said electric circuit.
24 . The process of claim 23 , wherein said fuel is selected from the group consisting of hydrogen, methanol, ethanol, formaldehyde, and formic acid.