Bifunctional (rechargeable) air electrodes comprising a corrosion-resistant outer layer and conductive inner layer
View Patent ↗Performance, properties and stability of bifunctional air electrodes may be improved by using modified current collectors, and improving water wettability of air electrode structures. This invention provides information on creating non-corroding, electrically rechargeable, bifunctional air electrodes. In some embodiments, this bifunctional air electrode includes a corrosion-resistant outer layer and an electrically conductive inner layer. In some embodiments, this bifunctional air electrode includes titanium suboxides formed by reducing titanium dioxide. Titanium suboxides may be corrosion-resistant and electrically conductive.
1. A bifunctional air electrode for a metal-air battery or cell, said air electrode comprising:
at least one current collector having:
a corrosion-resistant outer layer comprising TiC; and
a conductive inner layer comprising Ti; and
an air permeable, hydrophobic catalytic membrane,
wherein the corrosion-resistant outer layer has a greater corrosion resistance than the conductive inner layer and the conductive inner layer has a higher level of electrical conductivity than the corrosion-resistant outer layer.
2. The bifunctional air electrode of claim 1 , wherein the conductive inner layer is sandwiched within or coated by the corrosion-resistant outer layer.
3. The bifunctional air electrode of claim 1 , wherein the conductive inner layer further comprises at least one of the following: LiVTiO 4 , LiVTiO 3 , or LaTiO 3 .
4. The bifunctional air electrode of claim 1 , wherein fullerenes are electrochemically deposited from either an aqueous or non-aqueous solvent on the current collector.
5. The bifunctional air electrode of claim 1 , wherein carbon nanotubes (CNT) are deposited on the current collector.
6. The bifunctional air electrode of claim 1 , wherein the current collector further comprises glassy carbon that is coated on a substrate with a resin and pyrolysed in an inert atmosphere.
7. The bifunctional air electrode of claim 1 , wherein the corrosion-resistant outer layer comprises a powder coating that coats the conductive inner layer.
8. The bifunctional air electrode of claim 1 , further comprising a porous carbon-based coating on the current collector.
9. The bifunctional air electrode of claim 1 , further comprising a catalytic membrane that includes a catalyst selected from the group consisting of: metals, salts, or compounds containing one or more of the following: Mn, Co, Pt, Mo, Pd, or mixtures thereof.
10. The bifunctional air electrode of claim 1 , wherein the catalytic membrane acts as a catalyst to affect the reduction of oxygen or the generation of oxygen from water.
11. The bifunctional air electrode of claim 10 , wherein the catalytic membrane further comprises an air permeable, silicone rubber.
12. The bifunctional air electrode of claim 10 , wherein the catalytic membrane comprises an air permeable and hydrophobic material comprising at least one of the following: dimethyl silicone, fluorosilicone, nitrile silicone, natural rubber, ethyl cellulose, or low density polyethylene.
13. A bifunctional air electrode for a metal-air battery or cell comprising:
a current collector comprising:
a corrosion-resistant outer layer comprising TiC; and
a conductive inner layer comprising Ti; and
a catalytic membrane that is attached to a surface of the current collector,
wherein the catalytic membrane is air permeable and hydrophobic.
14. The bifunctional air electrode of claim 13 , wherein at least a portion of the conductive inner layer is sandwiched within or coated by the corrosion-resistant outer layer.
15. The bifunctional air electrode of claim 14 , wherein the current collector further comprises a perforated material, an expanded screen, or a woven structure.
16. The bifunctional air electrode of claim 14 , wherein the conductive inner layer further comprises LiVTiO 4 , LiVTiO 3 , LaTiO 3 , or any combination thereof.
17. The bifunctional air electrode of claim 14 , wherein the corrosion-resistant outer layer further comprises a powder coating.
18. The bifunctional air electrode of claim 14 , wherein the catalytic membrane comprises a porous carbon-based coating.
19. The bifunctional air electrode of claim 14 , wherein the catalytic membrane comprises glassy carbon.
20. The bifunctional air electrode of claim 14 , wherein the current collector further comprises fullerenes.
21. The bifunctional air electrode of claim 14 , wherein the current collector further comprises carbon nanotubes.
22. The bifunctional air electrode of claim 14 , wherein the catalytic membrane further comprises a catalyst comprising Mn, Co, Pt, Mo, Pd, any salt thereof, or any mixture thereof.
23. The bifunctional air electrode of claim 14 , wherein the catalytic membrane affects the reduction of oxygen or the generation of oxygen from water.
24. The bifunctional air electrode of claim 14 , wherein the catalytic membrane further comprises an air permeable silicone rubber.
25. The bifunctional air electrode of claim 14 , wherein the catalytic membrane further comprises an air permeable and hydrophobic material comprising dimethyl silicone, fluorosilicone, nitrile silicone, natural rubber, ethyl cellulose, low density polyethylene, or any combination thereof.