Inorganic microporous ion exchange membranes for redox flow batteries
A composite structure comprising a layer of zeolite having a high silica to alumina ratio supported on a support layer acts as a separator in a redox flow battery. The zeolite can be either supported on a rigid substrate, such as alumina, or a flexible substrate, such as a polymeric film. The polymeric film, in particular, can be an ion exchange membrane such as Nafion. The zeolite layer with a high silica to aluminum ratio provides a long-lasting separator for redox flow batteries.
1. A redox flow battery comprising:
a first oxidizing reaction chamber and a second reducing reaction chamber separated by a separator;
wherein said separator comprises a zeolite layer on a support, wherein said zeolite layer comprises aluminosilicate having a silicon to aluminum ratio of at least 10;
wherein said battery operates on electrode reactions of dissolved redox metal ion couples separated by said separator.
2. The redox flow battery claimed in claim 1 wherein said support layer is alumina or other acid-resistant ceramic materials.
3. The redox flow battery claimed in claim 1 wherein said support layer comprises a polymer film.
4. The redox flow battery claimed in claim 3 wherein said polymer film is an ion exchange membrane.
5. The redox flow battery claimed in claim 4 wherein said ion exchange membrane is selected from the group consisting of perfluorosulfonic acid and polybenzylimidazole.
6. The redox flow battery claimed in claim 3 wherein said separator comprises from about 1% to about 70% percent zeolite and from about 99% to about 30% polymer.
7. The redox flow battery claimed in claim 2 wherein said redox flow battery is one of a vanadium battery, zinc-cerium battery, zinc-bromine battery, iron chromium battery, vanadium bromine battery and sodium polysulfide-bromine battery.
8. A redox flow battery comprising:
a first oxidizing reaction chamber and a second reducing reaction chamber separated by a separator;
wherein said separator comprises a zeolite layer on a support, said zeolite layer comprising aluminosilicate having a silicon to aluminum ratio of at least 10; and
wherein said redox flow battery is one of a vanadium battery, zinc-cerium battery, zinc-bromine battery, iron chromium battery, vanadium bromine battery and sodium polysulfide-bromine battery.
9. The redox flow battery claimed in claim 8 wherein said silicon to aluminum ratio is from 10 to 50.
10. A redox flow battery comprising:
a first oxidation reaction chamber, a second reducing reaction chamber separated by a separator;
wherein said battery operates on electrode reactions of dissolved redox metal ion couples separated by said separator;
wherein said separator comprises a zeolite layer on a support;
wherein said zeolite layer has a silicon to aluminum ratio of 10 to 50.