Three Battery Awards

1. High efficiency, energy and power density (600 W/kg); cost /
cycling life only needs to be below $2/kW/hr.

2. Low cost (< 10 cents/kW-hr); efficiency, energy and power density
might not be too good.

3. Low cost, high energy and power density; Efficiency only needs to
be above 60%


Bret Cahill

Bret Cahill wrote:
>
> 1. High efficiency, energy and power density (600 W/kg); cost /
> cycling life only needs to be below $2/kW/hr.
>
> 2. Low cost (< 10 cents/kW-hr); efficiency, energy and power density
> might not be too good.
>
> 3. Low cost, high energy and power density; Efficiency only needs to
> be above 60%
>
> Bret Cahill

Find a universe with different thermodynamics and economics.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2

> > 1. *High efficiency, energy and power density (600 W/kg); *cost /
> > cycling life only needs to be below $2/kW/hr.

Make that 600 W-hr/kg.

> > 2. *Low cost (< 10 cents/kW-hr); *efficiency, energy and power density
> > might not be too good.

> > 3. *Low cost, high energy and power density; *Efficiency only needsto
> > be above 60%

> Find a universe with different thermodynamics and economics.

It should be easier to find 3 batteries that can fit the criteria
above than one super battery.

At a minimum it would help prove the limits to battery improvements
like Betz for wind power and Carnot for heat engines.


Bret Cahill

"Bret Cahill" <(E-Mail Removed)> wrote in message news:9a8b2695-fc66-4db1-909b-(E-Mail Removed)...
> 1. High efficiency, energy and power density (600 W/kg); cost /
> cycling life only needs to be below $2/kW/hr.
>
> 2. Low cost (< 10 cents/kW-hr); efficiency, energy and power density
> might not be too good.
>
> 3. Low cost, high energy and power density; Efficiency only needs to
> be above 60%
>
>
> Bret Cahill
>
>

There are wonderful batteries out there, and advances are made constantly, to many types of rechargable electro chemical cells.

One of the interesting ones I looked at lately is the (stabilized) Lithium Sulfur battery. Example development :
http://www.sionpower.com/pdf/article...ources2004.pdf
Gets 300 Wh/kg energy density currently, and there is little in the way of going to 400 or 500 Wh/kg. Power density is adequate for
EVs, and low temperature (cold wheather) behavior is excellent. If Lithium becomes scarce, there should be little problem switching
to another alkali metal such as Potassium or Sodium, with only small reduction of energy density. On the downside, recharge cycle
lifetime is still poor (250 - 500 cycles) and cost is high right now. But as always, volume production can change cost.

A really low cost, high capacity cell, with great power density and many (thousands) of lifetime cycles is the 'good old' Sodium
Sulfur battery.
Theoretical energy density is about 800 Wh/kg, current cells operate at around 250 Wh/kg.
Opponents claim safety issues are the main problems for this battery. These problems can be addressed, but it is doubtful that
automotive manufacturers will use this cell in large volumes, simply because of fear of safety issues. The ideal automotive battery
might not exist, because fair and conservative thinking is in the way of high volume use....

I looked at several out-of-the-box ideas for a super battery : Here is one theoretical one : Sodium Fluoride electro chemical cells.
Theoretical energy density of 3690 Wh/kg.
Many engineering issues remain.. One big issue : We need to find a way to store Fluorine gas. This might be similar to the problem
of storing hydrogen gas in hydrogen powered vehicles. Interesting overlap of engineering issues huh ?

Rob

On Sep 15, 4:38*pm, "Rob Dekker" <r...@verific.com> wrote:
> "Bret Cahill" <BretCah...@aol.com> wrote in messagenews:9a8b2695-fc66-4db1-909b-(E-Mail Removed)...
> > 1. *High efficiency, energy and power density (600 W/kg); *cost /
> > cycling life only needs to be below $2/kW/hr.
>
> > 2. *Low cost (< 10 cents/kW-hr); *efficiency, energy and power density
> > might not be too good.
>
> > 3. *Low cost, high energy and power density; *Efficiency only needsto
> > be above 60%
>
> > Bret Cahill
>
> There are wonderful batteries out there, and advances are made constantly, to many types of rechargable electro chemical cells.
>
> One of the interesting ones I looked at lately is the (stabilized) Lithium Sulfur battery. Example development :http://www.sionpower.com/pdf/article...ources2004.pdf
> Gets 300 Wh/kg energy density currently, and there is little in the way of going to 400 or 500 Wh/kg. Power density is adequate for
> EVs, and low temperature (cold wheather) behavior is excellent. If Lithium becomes scarce, there should be little problem switching
> to another alkali metal such as Potassium or Sodium, with only small reduction of energy density.

That is highly doubtful because of inability of stable passivating
film formation on Sodium
or Potassium. In overall, Li is so popular not only because it is the
lightest of the energetic
metalls, but also because of high ionic conductivity and solubulity of
its salts.
Na and K do not share this nice property.

> On the downside, recharge cycle
> lifetime is still poor (250 - 500 cycles) and cost is high right now. Butas always, volume >production can change cost.

Some processes are inherently more expensive than others. For example
CVD or othe vacuum
thin film deposition processes (used to make Li/S battery) are always
going to be more
expensive than slurry casting used in traditional Li-ion.

> A really low cost, high capacity cell, with great power density and many (thousands) of lifetime cycles is the 'good old' Sodium
> Sulfur battery.
> Theoretical energy density is about 800 Wh/kg, current cells operate at around 250 Wh/kg.
> Opponents claim safety issues are the main problems for this battery. These problems can be addressed, but it is doubtful that
> automotive manufacturers will use this cell in large volumes, simply because of fear of safety issues. The ideal automotive battery
> might not exist, because fair and conservative thinking is in the way of high volume use....

Conservative thinking has its uses. As statistics of Chem.Abstracs
shows, 95% of new ideas
turn out to be counter-productive.
Does not mean we should not try new things, but we should keep in mind
that "old" things
while having well known and understood problems and limitations,
are also tested under huge test matrix of various practical
situations. New ideas are
only tested by gedanken experiments (which test matrix is in turn
limited by imagination
of the thinker).

>
> I looked at several out-of-the-box ideas for a super battery : Here is one theoretical one : Sodium Fluoride electro chemical cells.
> Theoretical energy density of 3690 Wh/kg.
> Many engineering issues remain.. One big issue : We need to find a way tostore Fluorine gas. This might be similar to the problem
> of storing hydrogen gas in hydrogen powered vehicles. Interesting overlapof engineering >issues huh ?

Actually F2 is not that difficult to store. It passivates aluminum,
for example,
and you can keep it in Teflon.

But in addition to its aggressiveness, it is the most poisonous
compounds known to man.
I doubt that anybody in clear mind would suggest putting it into cars.

Regards,
Yevgen




>
> Rob

"Uncle Al" <(E-Mail Removed)> wrote in message news:(E-Mail Removed)...
> Bret Cahill wrote:
>>
>> 1. High efficiency, energy and power density (600 W/kg); cost /
>> cycling life only needs to be below $2/kW/hr.
>>
>> 2. Low cost (< 10 cents/kW-hr); efficiency, energy and power density
>> might not be too good.
>>
>> 3. Low cost, high energy and power density; Efficiency only needs to
>> be above 60%
>>
>> Bret Cahill
>
> Find a universe with different thermodynamics and economics.

Hi Al,

We do not need a new universe or different thermodynamics to design batteries with jaw-dropping characteristics.
The current universe offers a virtual infinite amount of ways to make batteries.

Even in the (one) group of alkali-halogen salt electrochemical cells there are amazing possibilities. For example Sodium Iodine has
a theoretical energy density of 600 Wh/kg. Sodium Chloride (table salt) can store 1913 Wh/kg and Sodium Fluoride (the stuff in tap
water to prevent cavities) checks in a whopping 3690 Wh/kg.

There are just immense engineering challenges to actually build such cells. Engineering difficulties, safety issues etc are the
problem. And fear of the unkown. Not the theory and not the laws of physics. Nature gave us a lot of building blocks to play with.
We are just getting started in this game....

Rob

> --
> Uncle Al
> http://www.mazepath.com/uncleal/
> (Toxic URL! Unsafe for children and most mammals)
> http://www.mazepath.com/uncleal/lajos.htm#a2

"Yevgen Barsukov" <(E-Mail Removed)> wrote in message news:79c01af6-55e3-41fc-9be7-(E-Mail Removed)...
On Sep 15, 4:38 pm, "Rob Dekker" <r...@verific.com> wrote:
> > "Bret Cahill" <BretCah...@aol.com> wrote in messagenews:9a8b2695-fc66-4db1-909b-(E-Mail Removed)...
> > > 1. High efficiency, energy and power density (600 W/kg); cost /
> > > cycling life only needs to be below $2/kW/hr.
> >
> > > 2. Low cost (< 10 cents/kW-hr); efficiency, energy and power density
> > > might not be too good.
> >
> > > 3. Low cost, high energy and power density; Efficiency only needs to
> > > be above 60%
> >
> > > Bret Cahill
> >
> > There are wonderful batteries out there, and advances are made constantly, to many types of rechargable electro chemical cells.
> >
> > One of the interesting ones I looked at lately is the (stabilized) Lithium Sulfur battery. Example development
> > :http://www.sionpower.com/pdf/article...ources2004.pdf
> > Gets 300 Wh/kg energy density currently, and there is little in the way of going to 400 or 500 Wh/kg. Power density is adequate
> > for
> > EVs, and low temperature (cold wheather) behavior is excellent. If Lithium becomes scarce, there should be little problem
> > switching
> > to another alkali metal such as Potassium or Sodium, with only small reduction of energy density.
>
> That is highly doubtful because of inability of stable passivating
> film formation on Sodium or Potassium.
> In overall, Li is so popular not only because it is the
> lightest of the energetic
> metalls, but also because of high ionic conductivity and solubulity of
> its salts.
> Na and K do not share this nice property.

I agree. Lithium is almost perfect for batteries. But, IMHO Lithium is best preserved for portable electronics. PHEVs and EVs would
need something else.
Large scale use of Lithium for PHEVs would quite rapidly deplete the limited amount of lithium salt that the world has in readily
harvestable form. That would almost certainly cause a Lithium shortage and immense price hikes for Lithium. So much that an
alternative will be needed very quickly.
Sodium is far cheaper and theoretically pretty decent. So if we can overcome the challenges of Sodium, then we sure have a winning
material for the electric vehicles of the future.

Do you think that some of the issues with Sodium (and Potassium) might be resolved when we would use a nano structure (like the
Stanford nanowire design) on the anode ?

> > On the downside, recharge cycle
> > lifetime is still poor (250 - 500 cycles) and cost is high right now. But as always, volume >production can change cost.
>
> Some processes are inherently more expensive than others. For example
> CVD or othe vacuum
> thin film deposition processes (used to make Li/S battery) are always
> going to be more
> expensive than slurry casting used in traditional Li-ion.

Sure. However, if you would have told someone 100 years ago that we could make an computation machine that contains 100 million
switching devices, that can do 1 billion operations per second, is the size of a post stamp and can be produced for about $10, then
they would have declared you a nutcase...

> > A really low cost, high capacity cell, with great power density and many (thousands) of lifetime cycles is the 'good old' Sodium
> > Sulfur battery.
> > Theoretical energy density is about 800 Wh/kg, current cells operate at around 250 Wh/kg.
> > Opponents claim safety issues are the main problems for this battery. These problems can be addressed, but it is doubtful that
> > automotive manufacturers will use this cell in large volumes, simply because of fear of safety issues. The ideal automotive
> > battery
> > might not exist, because fair and conservative thinking is in the way of high volume use....
>
> Conservative thinking has its uses. As statistics of Chem.Abstracs
> shows, 95% of new ideas
> turn out to be counter-productive.
> Does not mean we should not try new things, but we should keep in mind
> that "old" things
> while having well known and understood problems and limitations,
> are also tested under huge test matrix of various practical
> situations. New ideas are
> only tested by gedanken experiments (which test matrix is in turn
> limited by imagination
> of the thinker).
>

The Sodium Sulfur battery is not really a new idea. It is also a commercial and technical success for grid-storage systems (heavily
used in Japan).
It's use in vehicles however is not likely because of fear of safety issues.
Heck, even the perfectly safe Zebra (NiNaCl) battery is not yet a huge hit yet with EVs.
Of course, Lithium price hikes can easily make the much cheaper molten salt batteries pretty darn interesting again.

>
> > I looked at several out-of-the-box ideas for a super battery : Here is one theoretical one : Sodium Fluoride electro chemical
> > cells.
> > Theoretical energy density of 3690 Wh/kg.
> > Many engineering issues remain.. One big issue : We need to find a way to store Fluorine gas. This might be similar to the
> > problem
> > of storing hydrogen gas in hydrogen powered vehicles. Interesting overlap of engineering >issues huh ?
>
> Actually F2 is not that difficult to store. It passivates aluminum,
> for example, and you can keep it in Teflon.
>
>
> But in addition to its aggressiveness, it is the most poisonous
> compounds known to man.
> I doubt that anybody in clear mind would suggest putting it into cars.
>

It was a theoretical example. To continue the 'gedanken experiment', if we could find a cathode design with an immense surface area,
we may be able to store Fluorine gas in the atomic nooks and cracks. Maybe it would stay there even at atmospheric pressure, so that
it won't escape even if the battery gets crushed... Engineering challenge only...
If that is still considered unsafe, maybe we can store Cl2 gas, which is a lot less toxic. The NaCl system yields 1913 Wh/kg
theoretical. Enough for most people...

Rob

> Regards,
> Yevgen
>


>
> Rob

On Sep 15, 6:32*pm, "Rob Dekker" <r...@verific.com> wrote:
> "Yevgen Barsukov" <evgen...@gmail.com> wrote in messagenews:79c01af6-55e3-41fc-9be7-(E-Mail Removed)...
>
> On Sep 15, 4:38 pm, "Rob Dekker" <r...@verific.com> wrote:
>
>
>
> > > "Bret Cahill" <BretCah...@aol.com> wrote in messagenews:9a8b2695-fc66-4db1-909b-(E-Mail Removed)...
> > > > 1. High efficiency, energy and power density (600 W/kg); cost /
> > > > cycling life only needs to be below $2/kW/hr.
>
> > > > 2. Low cost (< 10 cents/kW-hr); efficiency, energy and power density
> > > > might not be too good.
>
> > > > 3. Low cost, high energy and power density; Efficiency only needs to
> > > > be above 60%
>
> > > > Bret Cahill
>
> > > There are wonderful batteries out there, and advances are made constantly, to many types of rechargable electro chemical cells.
>
> > > One of the interesting ones I looked at lately is the (stabilized) Lithium Sulfur battery. Example development
> > > :http://www.sionpower.com/pdf/article...ources2004.pdf
> > > Gets 300 Wh/kg energy density currently, and there is little in the way of going to 400 or 500 Wh/kg. Power density is adequate
> > > for
> > > EVs, and low temperature (cold wheather) behavior is excellent. If Lithium becomes scarce, there should be little problem
> > > switching
> > > to another alkali metal such as Potassium or Sodium, with only small reduction of energy density.
>
> > That is highly doubtful because of inability of stable passivating
> > film formation on Sodium or Potassium.
> > In overall, Li is so popular not only because it is the
> > lightest of the energetic
> > metalls, but also because of high ionic conductivity and solubulity of
> > its salts.
> > Na and K do not share this nice property.
>
> I agree. Lithium is almost perfect for batteries. But, IMHO Lithium is best preserved for portable electronics. PHEVs and EVs would
> need something else.
> Large scale use of Lithium for PHEVs would quite rapidly deplete the limited amount of lithium salt that the world has in readily
> harvestable form. That would almost certainly cause a Lithium shortage and immense price hikes for Lithium. So much that an
> alternative will be needed very quickly.

Automotive industry is very suitable for recycling. For example, Lead
from Lead Acid batteries are now the most recycled material on earth,
with 95% recycling level. Most likely it is
due to
1) inherent high level of standartization present in automotive
industry
2) strict regulations.
3) large size of batteries, which asks for a centralized handling

I think regulations for recycling of Li-ion batteries will be
tightened soon anyway, just for the safety and toxicity reasons, and
larger size of automotive batteries will allow to
achieve similar levels of recycling for Li.


> Sodium is far cheaper and theoretically pretty decent. So if we can overcome the challenges of Sodium, then we sure have a winning
> material for the electric vehicles of the future.

I would love to see some Na batteries, but challenges are immense.
Bad solubility in organic solvent, extreme reactivity, no passivation
layer,
hard to intercalate into anything.
Most likely Na batteries made in observable future will be
1) solid state thin film (because good solid electrolytes exists, like
NASICON)
or
2) at high temperature using molten Na
3) or very low rate of discharge


>
> Do you think that some of the issues with Sodium (and Potassium) might beresolved when we would use a nano structure (like the
> Stanford nanowire design) on the anode ?

Nano-structure would need to be self-replicating, reversible, e.g.
after dissolution / redeposition it needs to be preserved. That is the
main challenge.

Similar problem exists with new innovative cathodes. Indeed many
simple salts
like oxides and flourides are great oxidizing agents with very high
energy densities and
voltages vs Li (see works of Tarascon, for example this one:
http://www.ncbi.nlm.nih.gov/pubmed/1...?dopt=Abstract
).
But because they are non-conductive, have bad diffusion coefficients
and their crystalline structure is lost during reduction, there are
still not
batteries made with them.

If somebody figures a way to make a reversible over many cycles and
electrically counductive nano-structure with these materials, this
will be a hit.
Note that even LiFePO4 initially was considered unsuitable because of
bad conductivity,
but nano-manufacturing and carbonization later solved this problem to
make it a "star" of
todays battery landscape.



>
> > > On the downside, recharge cycle
> > > lifetime is still poor (250 - 500 cycles) and cost is high right now.But as always, volume >production can change cost.
>
> > Some processes are inherently more expensive than others. For example
> > CVD or othe vacuum
> > thin film deposition processes (used to make Li/S battery) are always
> > going to be more
> > expensive than slurry casting used in traditional Li-ion.
>
> Sure. However, if you would have told someone 100 years ago that we couldmake an computation machine that contains 100 million
> switching devices, that can do 1 billion operations per second, is the size of a post stamp and can be produced for about $10, then
> they would have declared you a nutcase...

I think the case here is somewhat different. I would rather compare
press-printing
process with making hand-written books. Sure you can highly train the
writer with modern
psicho-lingustic engineering techniques, but a press is still going to
beat it.
Note that optimizing the press will be also done using modern
techniques...

> > > A really low cost, high capacity cell, with great power density and many (thousands) of lifetime cycles is the 'good old' Sodium
> > > Sulfur battery.
> > > Theoretical energy density is about 800 Wh/kg, current cells operate at around 250 Wh/kg.
> > > Opponents claim safety issues are the main problems for this battery.These problems can be addressed, but it is doubtful that
> > > automotive manufacturers will use this cell in large volumes, simply because of fear of safety issues. The ideal automotive
> > > battery
> > > might not exist, because fair and conservative thinking is in the wayof high volume use....
>
> > Conservative thinking has its uses. As statistics of Chem.Abstracs
> > shows, 95% of new ideas
> > turn out to be counter-productive.
> > Does not mean we should not try new things, but we should keep in mind
> > that "old" things
> > while having well known and understood problems and limitations,
> > are also tested under huge test matrix of various practical
> > situations. New ideas are
> > only tested by gedanken experiments (which test matrix is in turn
> > limited by imagination
> > of the thinker).
>
> The Sodium Sulfur battery is not really a new idea. It is also a commercial and technical success for grid-storage systems (heavily
> used in Japan).
> It's use in vehicles however is not likely because of fear of safety issues.
> Heck, even the perfectly safe Zebra (NiNaCl) battery is not yet a huge hit yet with EVs.
> Of course, Lithium price hikes can easily make the much cheaper molten salt batteries pretty >darn interesting again.
>
It could find some uses in large scale stationary applications, where
high temperature
and slow start-up is not a problem, and structural integrity is not
under
attack of vibrations and uncertainties of a vehicle.
Same story as with fuel-cells, they show best efficiency at high
temperatures, so
only real applications we see now are the molten phosphate fuel-cells
in MWt size range.


>
>
>
>
> > > I looked at several out-of-the-box ideas for a super battery : Here is one theoretical one : Sodium Fluoride electro chemical
> > > cells.
> > > Theoretical energy density of 3690 Wh/kg.
> > > Many engineering issues remain.. One big issue : We need to find a way to store Fluorine gas. This might be similar to the
> > > problem
> > > of storing hydrogen gas in hydrogen powered vehicles. Interesting overlap of engineering >issues huh ?
>
> > Actually F2 is not that difficult to store. It passivates aluminum,
> > for example, and you can keep it in Teflon.
>
> > But in addition to its aggressiveness, it is the most poisonous
> > compounds known to man.
> > I doubt that anybody in clear mind would suggest putting it into cars.
>
> It was a theoretical example. To continue the 'gedanken experiment', if we could find a cathode design with an immense surface area,
> we may be able to store Fluorine gas in the atomic nooks and cracks. Maybe it would stay there even at atmospheric pressure, so that
> it won't escape even if the battery gets crushed... Engineering challengeonly...
> If that is still considered unsafe, maybe we can store Cl2 gas, which is a lot less toxic. The NaCl system yields 1913 Wh/kg
> theoretical. Enough for most people...

I think Tarascon approach converges with your idea to somehow
encapsulate F2.
You will lose some energy in the binding energy of encapsulation.
So you could just as well use Flourides and oxides, that already have
very high oxidative
potential and will give high voltage vs Li.


Regards,
Yevgen

>
> Rob
>
> > Regards,
> > Yevgen
>
> > Rob
>
>

"Yevgen Barsukov" <(E-Mail Removed)> wrote in message news:a854bf5d-458b-470d-8bb7-(E-Mail Removed)...
On Sep 15, 6:32 pm, "Rob Dekker" <r...@verific.com> wrote:
......
> > > > One of the interesting ones I looked at lately is the (stabilized) Lithium Sulfur battery. Example development
> > > > :http://www.sionpower.com/pdf/article...ources2004.pdf
> > > > Gets 300 Wh/kg energy density currently, and there is little in the way of going to 400 or 500 Wh/kg. Power density is
> > > > adequate
> > > > for
> > > > EVs, and low temperature (cold wheather) behavior is excellent. If Lithium becomes scarce, there should be little problem
> > > > switching
> > > > to another alkali metal such as Potassium or Sodium, with only small reduction of energy density.
>
> > > That is highly doubtful because of inability of stable passivating
> > > film formation on Sodium or Potassium.
> > > In overall, Li is so popular not only because it is the
> > > lightest of the energetic
> > > metalls, but also because of high ionic conductivity and solubulity of
> > > its salts.
> > > Na and K do not share this nice property.
> >
> > I agree. Lithium is almost perfect for batteries. But, IMHO Lithium is best preserved for portable electronics. PHEVs and EVs
> > would
> > need something else.
> > Large scale use of Lithium for PHEVs would quite rapidly deplete the limited amount of lithium salt that the world has in
> > readily
> > harvestable form. That would almost certainly cause a Lithium shortage and immense price hikes for Lithium. So much that an
> > alternative will be needed very quickly.
>
> Automotive industry is very suitable for recycling. For example, Lead
> from Lead Acid batteries are now the most recycled material on earth,
> with 95% recycling level. Most likely it is
> due to
> 1) inherent high level of standartization present in automotive
> industry
> 2) strict regulations.
> 3) large size of batteries, which asks for a centralized handling
>
> I think regulations for recycling of Li-ion batteries will be
> tightened soon anyway, just for the safety and toxicity reasons, and
> larger size of automotive batteries will allow to
> achieve similar levels of recycling for Li.

Of course, recycling is essential for all vehicle components, but extra so for Lithium batteries.
However, recycling alone will not solve the looming Lithium shortage once we start using Lithium batteries for PHEVs and EVs.
Here is a report (thank you B. Richardson for the link) which outlines the supply constraints on Lithium :
http://www.evworld.com/library/lithium_shortage.pdf

There is also a follow-up report which addresses the issue in more detail :
http://www.meridian-int-res.com/Proj...Microscope.pdf

The link does not seem to work right now, but that report shows quite convincingly that Lithium shortages will occur very soon when
volume (tens of thousands) production of PHEV batteries (with 10 kWh) batteries starts.
Considering that the world cranks out 65 million new vehicles every year, it looks like Lithium based batteries will remain for the
most affluent only in the new PHEV world.
The rest of us will have to do with batteries of a different chemical composition. Most notably the Zebra or Zn-air.

> > Sodium is far cheaper and theoretically pretty decent. So if we can overcome the challenges of Sodium, then we sure have a
> > winning
> > material for the electric vehicles of the future.
>
> I would love to see some Na batteries, but challenges are immense.
> Bad solubility in organic solvent, extreme reactivity, no passivation
> layer,
> hard to intercalate into anything.
> Most likely Na batteries made in observable future will be
> 1) solid state thin film (because good solid electrolytes exists, like
> NASICON)
> or
> 2) at high temperature using molten Na
> 3) or very low rate of discharge
>

Thanks for info on NASICON solid electrolytes. I did not know about these.
Do they work better than beta-alumina (for high and low temperatures) ?

> >
> > Do you think that some of the issues with Sodium (and Potassium) might be resolved when we would use a nano structure (like the
> > Stanford nanowire design) on the anode ?
>
> Nano-structure would need to be self-replicating, reversible, e.g.
> after dissolution / redeposition it needs to be preserved. That is the
> main challenge.
>
> Similar problem exists with new innovative cathodes. Indeed many
> simple salts
> like oxides and flourides are great oxidizing agents with very high
> energy densities and
> voltages vs Li (see works of Tarascon, for example this one:
> http://www.ncbi.nlm.nih.gov/pubmed/1...?dopt=Abstract
> ).
> But because they are non-conductive, have bad diffusion coefficients
> and their crystalline structure is lost during reduction, there are
> still not batteries made with them.
>
> If somebody figures a way to make a reversible over many cycles and
> electrically counductive nano-structure with these materials, this
> will be a hit.
> Note that even LiFePO4 initially was considered unsuitable because of
> bad conductivity,
> but nano-manufacturing and carbonization later solved this problem to
> make it a "star" of
> todays battery landscape.

Interesting. Thanks for all this info, and the progress/problems of nano structures.
It seems to me however that nano structures address the issue of power density of batteries with existing chemistry (simply because
of their immense large exposed surface area). The Tarascon abstract seems to indicate that too. But what I see much less often is if
nano structures actually enable alternate chemistries (such as using Na instead of Li).

Also, you seem to really like LiFePO4. I know very little about that, other than that they address power density but compromise on
energy density.
Also they still use Lithium. So what is good about it and why do you consider it a star in today's battery landscape ?
I have not seen them in the store yet, not heard much about them for PHEVs and EVs...

>

..........
> > > > I looked at several out-of-the-box ideas for a super battery : Here is one theoretical one : Sodium Fluoride electro
> > > > chemical
> > > > cells.
> > > > Theoretical energy density of 3690 Wh/kg.
> > > > Many engineering issues remain.. One big issue : We need to find a way to store Fluorine gas. This might be similar to the
> > > > problem
> > > > of storing hydrogen gas in hydrogen powered vehicles. Interesting overlap of engineering >issues huh ?
> >
> > > Actually F2 is not that difficult to store. It passivates aluminum,
> > > for example, and you can keep it in Teflon.
> >
> > > But in addition to its aggressiveness, it is the most poisonous
> > > compounds known to man.
> > > I doubt that anybody in clear mind would suggest putting it into cars.
> >
> > It was a theoretical example. To continue the 'gedanken experiment', if we could find a cathode design with an immense surface
> > area,
> > we may be able to store Fluorine gas in the atomic nooks and cracks. Maybe it would stay there even at atmospheric pressure, so
> > that
> > it won't escape even if the battery gets crushed... Engineering challenge only...
> > If that is still considered unsafe, maybe we can store Cl2 gas, which is a lot less toxic. The NaCl system yields 1913 Wh/kg
> > theoretical. Enough for most people...
>
> I think Tarascon approach converges with your idea to somehow
> encapsulate F2.
> You will lose some energy in the binding energy of encapsulation.
> So you could just as well use Flourides and oxides, that already have
> very high oxidative
> potential and will give high voltage vs Li.

That makes sense : the energy density goes down because we need a lot of encapsulation material.

But what would the chemistry look like for such a cell using fluorides and oxides as you suggest ?
And wouldn't the electrode potential be determined by the (metal) oxides and no longer by the fluorides themselves ?
I looked at some fluoride-based chemistries using but ended up with rather low energy densities OR (if molten salt form) with very
high melting temps.
Maybe I'm not looking at this the right way.... OK. Here is my question : How can fluorides or oxides have high oxidative potential
by themselves ?

>
>
> Regards,
> Yevgen

Thanks for your responses Yevgen. It is a pleasure talking with somebody who really knows what they are talking about.
Seems to become a rare occurrence these days on the NGs.

One question : I am a big fan of the Zebra (NiNaCl) cells for PHEVs and EVs.
If you were to improve the current (especially energy density) performance and/or lowering the operating temperature, what would you
do differently in the cell design ?

Also, there is only one company (MES-DEA in Switzerland) that makes this type of batteries. Do you know why noone else makes them ?
The patents on NiNaCl and other molten-salt chemistries are from the 70's and should be free to use now.
Can anyone start making Zebra cells now ?

>
> Rob
>
> > Regards,
> > Yevgen
>
> > Rob
>
>

"Rob Dekker" <rob # verific.com> wrote
http://groups.google.com/group/sci.c...c2b19b0d?hl=en
[snipped non-germane lamentations]
recycling alone will not solve the looming Lithium shortage
once we start using Lithium batteries for PHEVs and EVs.
Here is a report (thank you B. Richardson for the link)
which outlines the supply constraints on Lithium :
http://www.evworld.com/library/lithium_shortage.pdf &
http://www.meridian-int-res.com/Proj...Microscope.pdf
>
hanson wrote:
Of course, any and all recycling has always been done
when it was/is and will be commercially economical
and profitable. --- ----- ------ --- No Green **** advice
is required for that.... ahahaha... Of course, the green
turds had to muzzle in & charge waste re-processing
fees & recycling-permit charges on the OEM, the user
and the recyuler... all counter productive taxes that are
possible cuz or the hordes of little Green idiots who
are the witless & unpaid enablers and facilitators for
the Green Sharpies who ****e'm like Hogan's goat....
ahahaha...
There's no difference between Oil hogs & Green shits.
>
Now, in classical green fashion, you naturally have not
recognized that your looming Lithium shortage is largely
artificial and simply engineered by speculators for the
investors in that Li market... done along the very same
recipe by which the oil bois are ****ing us a the pump....
>
The same gig, but much more serious is the Copper
issue precipitated by the coming mass introduction
of electric cars and the revamping and expansion of
the power grind... --- --- 3 weeks ago the Chairman of
the largest Copper/mining producer was on TV and
said what I just mentioned and added... "Come on in
folks!. Sink your investments into copper... for we are
running at capacity now and we have NOT found any
new untapped Copper ore deposits, anywhere on the
globe, despite looking for them for the last 20 years"...
>
Thanks for the laughs.. Your Green chicken are coming
home to roost.... ahahhaha.... ahahahanson