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Getting rid of fuel cell / flow battery membrane

  1. Jul 25, 2017 #1
    I am aware of laminar flow but would like to look for some other ways.
    Is it possible to block ions from flowing in the "wrong" direction by applying a magnetic field to the electrolyte and let neutral molecules pass through?
  2. jcsd
  3. Jul 30, 2017 #2
    Thanks for the thread! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post? The more details the better.
  4. Aug 1, 2017 #3
    As an example (which probably won't work but other combinations may), a magnetic field is setup to allow positively charged ions to flow from negative half cell to positive half cell but not the other way round.
    In the negative half cell, H2PO2- is oxidized to HPO32-, both ions are negatively charged thus won't flow to the positive half cell.
    In the positive half cell, VO2+ is reduced to VO2+, both ions are positively charged thus won't flow to negative half cell.
  5. Aug 8, 2017 #4
    You are leaving out the proton and hydroxide redox half reactions in your example, which complete the electrical circuit and generate movement of (at minimum) water between the electrodes. I don't think your proposed membrane-less scheme will work because the magnetic field strength is much weaker than other motive forces acting on the ions in solution.
  6. Aug 16, 2017 #5
    Yeah, looks like one reaction is acidic while the other is basic. Perhaps S22-/S42-,Fe3+/Fe2+ is a better example?
    How do you calculate other forces (diffusion?)?
  7. Aug 16, 2017 #6


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    Staff: Mentor

    Can you explain what would be the point of this?
  8. Aug 19, 2017 #7
    Ion exchange membrane is often a bottleneck in flow batteries, a membraneless system can reduce complexity and improve efficiency.
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