----- Original Message -----
From: Chris Zell
Where can we go beyond lithium? ... That's why the ultracap
approach is so exciting - it's a whole new way to fix the energy
storage problem.
Here is a "slant" on the bettery (better-battery technology) that
you will likely hear nowhere else. That could be because:
1) it is wrong, or
2) there is a fair amount of intentional disinformation out there,
or
3) both
Ultracapacitors will help - but are probably only "half" the
long-term answer to the bettery (better battery) ... in that there
is an underappreciated synergy between the capacitor and battery -
the so-called bat-cap. This is more than semantics - and more than
'just' a combination of two different and distinct electrical
parts. You have to merge the two in the design process itself to
get the synergy.
The idea is that the cap layer (thin and planar) carries/stores
the negative charge while the electrochemical ions of the battery
carry/store the positive. The result is somewhere in between
either device, but it does require an electrolyte, unlike the cap,
and the best way that you can merge the two dissimilarities is to
go with many thin flat layers using a solid electrolyte. Many
people who have analyzed the EEStor patent missed this key point
(mainly because the patent is artfully written to throw out a
number of red herrings).
Everyone on the cutting edge of batteries these days seems to be
throwing out false-leads ... why? for one thing - basically, all
of the important patents expired years ago (or are about to expire
now). Now we are down to improvements disguised as breakthroughs.
There is a good argument that lithium, as a charge carrier, is far
from ideal - even if it were cheap. And it is very expensive. Even
the present demand for small batteries for computers and
cell-phones has pushed the price of large capacity lithium way too
high for practical automobile transportation.
Plus lithium has a molecular weight of 7 and only one oxidation or
reduction state while carbon, which is a thousand times cheaper
(literally) as a commodity item, and has a molecular weight of
12 - less than double but triple the number of *usable* oxidation
or reduction states (all four are not usable). Less voltage
available per cell - but - all in all, for charge-retention per
unit weight and cost, carbon is preferable to any other material,
especially for the negative charge carrier (as an ultra-cap):
http://web.mit.edu/newsoffice/2006/batteries-0208.html
In terms of cost/weight per stored charge - for the positive side,
there is a good case of sodium. which is also low density, cheap,
ubiquitous and - best of all ! - there is available a
well-engineered (courtesy of FMC forty years ago) but largely
ignored solid electrolyte - beta alumina:
http://scienceservice.si.edu/001023.htm
This concept of sodium used with a solid electrolyte is almost
always mentioned in the context of NAS - or sodium sulfur, but I
have wondered for a long time why this could not broadened and
merged into the bat-cap category.
IOW the two positive face-surfaces of the thin (sandwiched planar)
cap (the negative terminal) substitute for the sulfur of the NAS,
drawing sodium ions physically through the solid electrolyte on
charging. This might require some kind of bellows type expansion
mechanism between the layers. If the negative charge carrier is a
layer of activated carbon (as in the MIT patent) then in effect
you have cut the cost and weight of the NAS in half. Before it was
already in the same weight per charge category as lithium - at a
tenth the cost but with one major drawback - which has kept it
from use as a small battery (and out of mass production).
The problem remains that beta alumina needs to be "warm" (450 K)
to conduct sodium ions, and even though this situation has been
remedied by a few hundred degrees since Ford gave up on the
project, there are practical solutions. (hint: you always have
plenty of waste heat with a hybrid).
I got an inkling description of a prototype NAS battery setup
yesterday that will blow the socks off of anything currently
available for battery power, including lithium and hydrides. This
WILL happen in the next few years, even in the face of budget
cuts, but - sadly because of lack of cooperation and the
free-market forces involved - that which is on the cutting edge
today (in at least a dozen labs) can be easily improved on if they
all were to share technology...
(this in the opinion of an outsider who would like to have some
EEStor shares, regardless of the fact that they missed a few
things).
Jones
