[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
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
ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org
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