A True Green Tech Battery: Quinone Flow Batteries (The Rhubarb Battery)


When you stop to think about it, plants do a hell of a lot more in the energy making and storing department than metals like lead and lithium do, right?  They wake up in the morning, make energy, stash it away, and do it again the next day after converting some of it into new growth.  Take that a step further and look at where oil comes from…  right, organic material.

So it stands to reason, albeit out of the box reason, that a battery using organic molecules (called quinones) found in plants like rhubarb (and oil, by the way), would be able to store energy. Thanks to the work of Michael J. Aziz, the Gene and Tracy Sykes Professor of Materials and Energy Technologies at the Harvard School of Engineering and Applied Sciences (SEAS), Roy G. Gordon, the Thomas Dudley Cabot Professor of Chemistry and Professor of Materials Science, and Alán Aspuru-Guzik, professor of chemistry and chemical biology, Harvard University announced on January 8th, this year, a flow-type battery based on an organic electrolyte.  Here’s the story, from The Harvard Gazette: Battery Offers Renewable Energy Breakthrough.  Here’s the SEAS press release.

This brings up an interesting question…  what exactly is a “flow battery”?


Flow battery technology has been around since the late 19th century, and it’s basically a design where two electrolytes are circulated through the battery, past the electrodes, to move ions between them, instead of between two electrode metals.  “The flow battery generates electricity when the liquid electrolytes, which are mixed with energy-storing materials, flow through the two-half cells and react with the electrodes in each side of the cell. Flow battery developers are experimenting with different types of energy storing materials, such as iron, vanadium, zinc and bromine.”

One of the better explanations is here, on Gigaom.com.  There’s also a good description on Electropaedia, here.  Here’s a nice, concise description of one of the more interesting attributes of a flow battery: “The power rating of the system is fixed and determined by the size and number of electrodes in the cell stacks, however the great advantage of this system is that it provides almost unlimited electrical storage capacity, the limitation being only the capacity of the electrolyte storage reservoirs. Opportunities for thermal management are also facilitated by using the electrolytes as the thermal working fluids as they are pumped through the cells.”

Most of the advantages of this type of design seem to point towards grid-level load-leveling storage, since flow battery technologies provide very high power and very high capacity.  Am I the only one thinking they’d work really well for EVs?  Apparently not.  From EVWorld: Flow Battery to Power QUANT e-Sportlimousine Concept.


…and a motorcycle already has a tank to hold liquids, right?  You want more capacity, add a larger tank.  Sounds familiar.  Also, you can “recharge” simply by replacing the electrolyte.

Here’s more on that car, and the nanoFLOWCELL tech.  Oh, and a snappy video with cool music.  And mermaids and shit.

OK, back to reality.  One of the big issues is designing a pumping system that will hold up, presumably since the electrolytes are fairly reactive, and EnerVault seems like they’ve been working on that for a while now, and have a grid-scale product nearing completion.  Read about it here, on greentechgrid: EnerVault Nears Completion of Its First Commercial-Scale Flow Battery.  Interestingly, about the same publication date as the Harvard team’s work.  Also, there’s the Redflow battery system.  So why is the “Rhubarb Solution” so cool?  Simply, cheap and abundant materials, unlike the common metal options now.

So.  Here’s the vision.  A scaleable, high-power better-density small EV-sized battery that is a standard size, with tanks that determine your capacity.  Let the DIY search begin.



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