[FoRK] Redox battery for EVs is recharged in minutes through electrolyte exchange

Eugen Leitl eugen at leitl.org
Thu Oct 22 08:36:58 PDT 2009


On Thu, Oct 22, 2009 at 10:49:46AM -0500, Reese wrote:

> >I have this neat idea. Why not taking liquid methanol, which
> >has half the energy density of diesel/gasoline, and use this
> >as one electrode in a redox pair, the other being air. You
> >don't have to carry the oxidant, and you lose mass as one 
> >electrode is consumed, since you vent the reaction products
> >(water and CO2) into air. I think I will call it a "fuel cell".
> 
> Given everything else that is going on with CO2, why would you want
> to vent more of it to the atmosphere?

Because an EV scales into weight regions which no ICE can
reach, since it can have regenerative braking, spike cache, in-wheel
motors and similar. Nevermind that ICE cars have about 23%
efficiency which can't be raised, while fuel cells are non-Carnot,
so DMFCs can go to 40% or higher (the methanol permeability of
the proton membrane has been fixed in the lab with multiple
nanocoatings, not yet in practice though).

So you burn way less fuel and at a higher efficiency.

Plus MeOH has more hydrogen than alcanes/aromates in gasoline/diesel, can be
made from methane (including direct methane oxidation) or 
renewables, so net CO2 can be neutral.

E.g. http://www.physorg.com/news159098987.html but presumably
you can drive this photonically, or via a electrosynthetic
route, presumably scaling down to very small facility scale, 
down to fridge-sized units.

Not that motor vehicles are the main culprit, in 2006 it was some 33%
of total CO2 emissions in the US. You can shrink this to below 10%
if you'd just substitute them with DMFCs.

Don't get me wrong, EVs will be there eventually, but methanol
is an excellent bridge technology to both EVs and hydrogen. See
http://www.amazon.com/Beyond-Oil-Gas-Methanol-Economy/dp/3527324224/
why this is so (Olah et al. are not entirely correct there though,
caveat lector).  

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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