Redox membrane-based flow fuel cell

Abstract

A flow fuel cell for use as a source of electrochemical energy with the membrane separating two flowing aqueous solutions with dissolved redox active components and electrodes of the second kind, wherein the membrane is made of a redox active synthetic metal polymer.

Description

RELATED US PATENT DOCUMENTS[0001]L. H. Thaller, Electrically rechargeable redox flow cell, U.S. Pat. No. 3,996,064, 1976.[0002]M. S. Kazacos, M. Kazacos, Stabilized vanadium electrolyte solutions for all-vanadium redox cells and batteries, U.S. Pat. No. 6,562,514, 2003.[0003]L. Nagels, H. Bohets, M. Jimidar, Potentiometric electrode, gradient polymer, uses and method of preparation thereof, US Patent 2008 / 0000290 A1[0004]J. H. Kim, D. G. Ryu, Y. L Yi, J. H. Park, Composition of polythiophenethiophene-based conductive polymers having high conductivity, transparency, waterproof property and a membrane prepared using the same, US patent US 2008 / 0293855 A1.[0005]C-H Hsu, F. P. Uckert, Water dispersible polyanilines made with polymeric acid colloids for electronics applications, US patent US 2008 / 0210910 A1.[0006]K. Asazawa, K. Yamada, H. Tanaka, Fuel Cell, US patent application publication US2010 / 0035111 A1[0007]N. Kocherginsky, Wang Zheng, Measurements of Redox Potential and Concentrat...

AI Technical Summary

Benefits of technology

"This patent describes a process for creating a membrane that can generate electricity when exposed to different substances. The membrane is made from a special type of polymer that has conductive properties. The process involves using different dopants and oxidants to create a redox system. The membrane can be used as a power source in a fuel cell without the need for expensive platinum electrodes. The process is also efficient and can be used with different oxidants and reducing agents. The membrane can be made from a variety of synthetic metals and can be stored in a stable form. Overall, this patent provides a way to create a membrane that can generate electricity and can be used in a fuel cell."

Problems solved by technology

Positive and small H′ ions have the highest diffusion coefficient and can present in high concentrations, leading to low internal electric resistance of the cell.

The problem with proton exchange membrane-based fuel cells, including direct methanol fuel cells, is that usually used oxygen reduction reaction, occurring at the cathode, is very slow and a catalyst is needed.

The problem becomes even more complicated because exchange currents for anode and cathode reactions on Pt can be limited by both ion transport in solutions and interface electron transfer, thus leading to the current-overpotential, i.e. it is necessary to use voltage higher than its thermodynamic equilibrium value to start and conduct fast electrochemical reaction.

Application of fuel cells in underwater vehicles has another problem.

Unlike ground and air transportation, these vehicles must carry both the fuel and the oxygen source because the oxygen concentration in water is insufficient to meet the vehicle power requirements.

Gaseous oxygen storage does not provide adequate storage densities, while liquid oxygen storage introduces challenges with handling and storage.

Solid-state oxygen sources such as sodium chlorate (NaClO3) and lithium perchlorate (LiClO4) possess high oxygen contents and are stable under ambient conditions; however, decomposition of these materials to gaseous oxygen typically employs thermal methods that are often difficult to start, stop, and control.

They can be used in submarine applications to accumulate, to store and to use electric energy when necessary, but have the major challenge, which is nonselective ionic and water migration through the ion-exchange membrane.

An electric organ of an eel Electrophorus electricus is a battery of biological membranes, which during excitation can generate voltages up to 1000V and currents up to 1 A. After purification these membranes are not stable and can not be used as a electrochemical power source in everyday life.

These electrochemical cells are called concentration elements, but they did not find practical applications because of the low generated voltage.

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