Metal foam capacitors and supercapacitors
A capacitor and supercapacitor design are based on metal-foam electrodes. An electrolytic capacitor has a metal foam dielectric (e.g., aluminum oxide, titanium oxide, iron oxide, or others). An electric double-layer supercapacitor has an electrode with metal foam (e.g., copper, nickel, titanium, iron, steel alloy, or aluminum) filled with activated carbon, or graphene, or metal foam with activated carbon foam, or any combination of these to enhance the electrical conductivity and thus the power and capacity of the cell. A pseudocapacitor device has an electrode with metal foam (e.g., iron, cobalt, nickel, copper, titanium, aluminum, magnesium, tin, manganese, and stainless steel, and their alloy foams) coated with an oxide- or hydroxide-based material containing highly active zones. The pseudocapacitor metal-foam electrode can also be filled with activated carbon in the form of a slurry to further enhance its capacity.
1 . A metal-foam-based capacitor device comprising:
a single-layer metal-foam anode electrode filled with an active material in a volumetric weight range of 0.2-1.8 grams per cubic centimeter and coated with a thermal metal-oxide layer on a surface of the electrode, wherein the capacitor device comprises an electric double-layer capacitor, and the active material wholly in a single layer.
2 . The device of claim 1 wherein the metal foam is at least one of aluminum, tantalum, titanium, cobalt, nickel, copper, or iron.
3 . The device of claim 1 wherein the thermal metal-oxide coating is formed via a thermal oxidation.
4 . The device of claim 1 wherein the metal-foam anode electrode is manufactured using freeze-casting.
5 . The device of claim 1 wherein the metal-foam anode electrode is formed using
thermal heat treatment at a temperature range of about 100 degrees Celsius to 800 degrees Celsius for a duration of from about 5 minutes to about 3 hours in an air atmosphere,
activated carbon is added in the form of a slurry mixture with deionized water and a binder in a volumetric weight range of 0.2-1.8 grams per centimeter, and
freeze-casting.
6 . A metal-foam-based electric double-layer supercapacitor cell device comprising:
two metal-foam electrodes filled with an active material in a volumetric weight range of 0.2-1.8 grams per cubic centimeter, wherein each of the two metal-foam electrodes comprises a metal foam and the active material wholly in a single layer,
the metal-foam electrodes comprise at least one electrode comprising a copper foam coated with tin.
7 . The device of claim 6 wherein at least one metal-foam electrode is at least one of nickel, titanium, iron, or steel alloy with a porosity range between 60 percent to 90 percent.
8 . The device of claim 7 wherein electroless plating is used to coat the copper foam electrode with tin (Sn).
9 . The device of claim 6 wherein the active material is added in the form of a slurry mixture with deionized water and a binder.
10 . The device of claim 6 wherein the active material filler is activated carbon or graphene in combination with a conventional electrolyte and separator.
11 . The device of claim 6 wherein the two metal-foam electrodes are manufactured using freeze-casting.
12 . The device of claim 6 wherein at least one of the two metal-foam electrodes are manufactured using
thermal heat treatment at a temperature range of about 100 degrees Celsius to 800 degrees Celsius for a duration of from about 5 minutes to about 3 hours in an air atmosphere,
activated carbon is added in the form of a slurry mixture with deionized water and a binder in a volumetric weight range of 0.2-1.8 grams per centimeter, and
freeze-casting.
13 . A metal-foam-based electrostatic capacitor cell device comprising:
two metal-foam electrodes coated or filled with an active material, or a combination in a volumetric weight range of 0.2-1.8 grams per cubic centimeter, wherein each of the two metal-foam electrodes comprises a metal foam and the active material wholly in a single layer, and
the metal-foam electrodes are coated with an active thermal coating layer with a thickness of between about 10 nanometers and about 500 nanometers via thermal oxidation.
14 . The device of claim 13 wherein the two metal-foam electrodes can be any one of or a combination of iron, cobalt, nickel, copper, titanium, aluminum, magnesium, tin, manganese, or stainless steel metal foams and their alloys with a porosity range from about 60 percent to 90 percent.
15 . The device of claim 13 wherein the anode and cathode active materials are a different combination of oxide- or hydroxide-based materials, or any combination, including at least one of Fe 2 O 3 , Fe 3 O 4 , FeOOH, MnO 2 , Mn 3 O 4 , Co 3 O 4 , CoO, SnO 2 , Cu 2 O, Cu(OH) 2 CuO, TiO 2 , NiO, or Ni(OH) 2 .
16 . The device of claim 15 wherein the oxide coating is formed via thermal heat treatment at a temperature range of about 100 degrees Celsius to 800 degrees Celsius for a duration of from about 5 minutes to about 3 hours in an air atmosphere.
17 . The device of claim 13 wherein activated carbon is added in the form of a slurry mixture with deionized water and a binder in a volumetric weight range of 0.2-1.8 grams per centimeter.
18 . The device of claim 13 wherein the metal-foam electrode is manufactured using at least one of freeze-casting, 3D printing, the space-holder technique, or dealloying processing.
19 . The device of claim 13 wherein the metal-foam electrode is formed using
thermal heat treatment at a temperature range of about 100 degrees Celsius to 800 degrees Celsius for a duration of from about 5 minutes to about 3 hours in an air atmosphere,
activated carbon is added in the form of a slurry mixture with deionized water and a binder in a volumetric weight range of 0.2-1.8 grams per centimeter, and
freeze-casting.