USE OF ANION-EXCHANGE MEMBRANE IN IRON-CHROMIUM LIQUID FLUID BATTERY

The present invention regarding the use of anion-exchange membranes for Fe/Cr redox cells belongs to the area of flow redox batteries (or flow redox cells). An anion exchange membrane works as a separator between the positive and negative electrodes in Fe/Cr redox flow cell. The said anion exchange membranes include those composed of quaternized-ammonium polyether ether ketone, quaternized-ammonium polyether sulfone ketone, or quaternary phosphonium salt functional groups, etc. The used anion exchange membrane, which consists of non-fluorinated polymer and has been tested well in fuel cells, has good anion selectivity for Cl - and cost much less in the present invention. Another advantage of using anion exchange membranes is that, as the internal conductivity inside the cell is no longer dependent on protons, it allows the lower concentration of hydrochloric acid in the electrolyte solution. Not only does it reduce the side reaction of hydrogen evolution but also it potentially makes the electrolyte solution less harmful to the environment. Thus, the use of anion exchange membranes for Fe/Cr flow batteries can lower their production cost while keeping their high efficiency and potentially reduce their harmful impact to the environment.