Sigh.  I'll try to spell it out for you.  I didn't realize EE's were chemically challenged.

Normally, a battery stores its energy by the difference in electric potential between the cathode and anode, which exchange electrons in an oxidation-reduction reaction.  One gets oxidized, the other reduced, and the electrons drop down in their potential making the trip.  This is what makes your electric motors go round as they pass by the magnets in the motor.

As this process occurs in the typical battery, the cathode gets dissolved and metal gets deposited on the anode, that's how you do plating.  Fully discharged, there's nothing left of the cathode, this batt is non-rechargeable and dead.  However, transition metals have several oxidation states they can exist in, so in rechargeable batts when the metal ion moves across the electrolyte solution to the anode it changes state but your cathode doesn't dissolve away.  When you recharge, you push the electrons back up on the cathode side, and it's ready to go again.  However, repeated cycles of this wear out both ccathode and anode so you can't keep doing it.  Rechargeable batt now dead also.

Flow batts get rid of the cathode and anode and replace them with liquids which are suspensions of nanoparticles in water.  You have a tank that holds charged up nano particles and a discharge tank, sorta like the gray water in your RV waste tank.  When you go to the filling station, you empty your discharged nanoelectrolyte tank and refill your charged tank.  You drive away.

At the filling station, your discharged nanoelectrolyte suspension gets recharged, by electricity generated from a non-ff source.  Then when the next customer shows up, this charged up stuff is pumped into his tank.  The fluid itself never disappears.

The nanoparticles are only necessary in order to turn what in normal batts are solids into a liquid you can pump and exchange easily.  The tinier the particles, the greater the density you can squeeze into a given volume without making the fluid too viscous to pump and keeping the particles suspended.  Big particles sink, you can't do this with them.  The greater the density of particles, the greater the energy density you can store this way.

Hopefully this is clear to the chemically challenged doomers inhabiting this website.

RE