Alkaline Membrane Fuel Cells and Apparatus and Methods for Supplying Water Thereto
A device to produce electricity by a chemical reaction without the addition of liquid electrolyte comprises an anode electrode, a polymer membrane electrolyte fabricated to conduct hydroxyl (OH—) ions, the membrane being in physical contact with the anode electrode on a first side of the membrane, and a cathode electrode in physical contact with a second side of the membrane. The anode electrode and cathode electrode contain catalysts, and the catalysts are constructed substantially entirely from non-precious metal catalysts. Water may be transferred to the cathode side of the membrane from an external source of water.
1 . A device to produce electricity by a chemical reaction without the addition of liquid electrolytes, the device comprising:
an anode electrode;
a polymer membrane electrolyte configured to conduct hydroxyl (OH—) ions, the membrane being in physical contact with the anode electrode on a first side of the membrane; and
a cathode electrode in physical contact with a second opposite side of the membrane;
wherein the anode electrode and cathode electrode contain catalysts, the catalysts being constructed substantially entirely from non-precious metal catalysts.
2 . The device of claim 1 where the membrane thickness is under about 30 micrometers.
3 . The device of claim 1 wherein the anode electrode and cathode electrode are prepared using a solution of substantially the same polymer from which the membrane is made.
4 . The device of claim 3 wherein the volume concentration of the alkali hydroxyl (OH—) ions in the polymer within the electrodes is at least about 5% higher than that of OH-ion volume concentration in the membrane.
5 . The device of claim 1 wherein the anode electrode and cathode electrode are prepared from a recast hydroxyl (OH—) ion conducting polymer of chemical composition different from which the membrane is made.
6 . The device of claim 1 further comprising at least one catalyst layer adjacent to the membrane configured with a mixture of non-precious catalyst and polymer solution on a support chosen from the group consisting of woven carbon, non-woven carbon, metal mesh, and metal foam.
7 . The device of claim 1 further comprising at least one catalyst layer configured with a mixture of non-precious catalyst and polymer solution and disposed directly on the membrane to form a catalyst coated membrane (“CCM”).
8 . The device of claim 7 wherein the CCM is prepared by: (a) direct air-spraying of a catalyst ink onto one side of the OH— ion conducting membrane placed on a heated vacuum table; and (b) direct air-spraying of the catalyst ink on the opposite side of the membrane.
9 . The CCM described in claim 8 wherein the overall thickness of the catalyst layer is less than about 5 micrometers.
10 . The CCM described in claim 8 wherein the catalyst ink is made by vigorous mixing of a metal or carbon supported non-precious catalyst with a solution of ionomer in water/alcohol mixture.
11 . The device of claim 1 further comprising at least one non-precious catalyst layer configured by impregnating the catalyst layer with a polymer solution.
12 . The device of claim 1 wherein at least one electrode further comprises a front layer of high volume concentration of non-precious metal catalyst in physical contact with a side of the membrane and is configured by the technique chosen from the group consisting of sputtering, e-beaming, and direct electro-less deposition.
13 . The device of claim 1 wherein the membrane further comprises a concentrated front layer of non-precious metal catalyst on at least one side of the membrane and is in physical contact with an electrode and is configured by the technique chosen from the group consisting of sputtering, e-beaming, and direct electro-less deposition.
14 . The device of claim 1 wherein at least one electrode further comprises a layer of an array of catalyst-coated micro-dendrites embedded into the membrane.