TheEEStory.com

larry,

The high k from Ti++ moving is highly unusual, and because the ionic bonding of the Ti is very weak in one direction, so it can move easily. This is because the hamiltonian (word Daniel thinks is above the level of readers here, but I disagree) is very flat for Ti ion movements (in fact depending on phase it can have a double dip, with two stable positions, or a single dip).

Those conditions do not pertain to the electron cloud, so although it will move the k available from this is very small.

"The polymer matrix will ensure high dielectric strength and the nanoparticles can enhance the dielectric constant by a factor of 3-10 according to linear composite theory. We will increase the dielectric constant another factor of 3-10 by exploiting POLARIZATION EXCHANGE COUPLING between the high-k particle and polar matrix through the amphiphile encapsulant".
We have already commented this, EE-Tom says those are vague statements accurately built to attract investor's money. Maybe, but would a serious scientist put his reputation in jeopardy by claiming things that are scientifically impossible ?

Absolutely not. What he says is all possible, though whether commercially practical he probably does not know. I guess LB films of any reasonable volume are expensive since each one is 1nm thin.

But he makes no claim anywhere for ED higher than 520J/cc (dielectric only) or 260J/cc (device-level).

His claim for the high-k particles is that they should increase ED by 30% (200J -> 260J device-level).

ee-tom wrote:

"The polymer matrix will ensure high dielectric strength and the nanoparticles can enhance the dielectric constant by a factor of 3-10 according to linear composite theory. We will increase the dielectric constant another factor of 3-10 by exploiting POLARIZATION EXCHANGE COUPLING between the high-k particle and polar matrix through the amphiphile encapsulant".
We have already commented this, EE-Tom says those are vague statements accurately built to attract investor's money. Maybe, but would a serious scientist put his reputation in jeopardy by claiming things that are scientifically impossible ?

Absolutely not. What he says is all possible, though whether commercially practical he probably does not know. I guess LB films of any reasonable volume are expensive since each one is 1nm thin.

But he makes no claim anywhere for ED higher than 520J/cc (dielectric only) or 260J/cc (device-level).

His claim for the high-k particles is that they should increase ED by 30% (200J -> 260J device-level).

Ducharme's material is based less on the k of the material and more on the field strength. As he quoted to me,

Stephen Ducharme wrote:

The polarization does not limit energy storage. Fundamentally, the electrostatic energy density in a dielectric is equal to the electric displacement (mainly the electric polarization) times the electric field. Even if the polarization essentially saturates, increasing the field increases the stored energy, but only linearly with the field instead of quadratically, as at low fields.

"we have developed Langmuir-Blodgett polymer films capable of storing electrical energy densities as high as 400 J/cm3 by taking advantage of the extremely high dielectric strength of vinylidene fluoride polymers. WE CAN ACHIEVE EVEN GREATER ENERGY DENSITY IN BULK CAPACITORS... by exploiting THE INCREASED DIELECTRIC CONSTANT of nanostructure-designed materials that incorporate several key innovations in polymer and nanoparticle synthesis, nanofabrication, and multiscale modeling".
Perhaps it's me, but when somebody talks about 400J/cm3 and immediately after says that even higher ED are achievable, I tend to believe it refers to such 400J/cm3, don't you agree ?

mjtimber:
did you ask mr. Ducharme if he has ever calculated a theoretical max ED, and what is the magnitude order of such limit, 100, 1000, 10,0000 ?
In his reply to you, Ducharme talks about saturation but only at a qualitative level (sooner or later, saturation occurs), not providing what we need here: a quantitative theoretical limit.

Basic, looking back at table 1 in the other paper, I see he energy density is for a 50% filling factor which should be plates and/or something else. So his 200 J/cc under the LB column now makes sense and matches up with the text comments of 400 J/cc. And the 275 should be 550 J/cc which should really impress y_po. So yes, it seems he can go a bit higher than 400 J/cc, but not 3-10 times higher (times 2) based simply on increased k factors.

Concerning mjtimber's comment that he said the energy density is not limited, I believe he said the poly breaks down above 3 GV/m (3 kV/micron) if there are at least 2 monolayers (molecular layers) but the 400 J/cc appears to already be calculated from 3.3 GV/m and k=8. Once you're past saturation, the extra energy stored is 8 times smaller because k=1. When saturation starts, k starts decreasing and maybe he's already into some saturation at 400 J/cc which could explain why he stated k~8. Now considering that the material is already near break down voltage at 400 J/cc, I don't we should infer from his comments that energy density is unlimited, nor even substantially higher than 400 J/cc.

But you made an elementary calculation, which resulted in your absolute max limit to energy storage.
The only assumption you did was the ionic number of the moving charge within the lattice (50 if I well remember), which itself was a very generous number; yet, under such conditions the calculated limit was 250J/cc.
Why Ducharme should not be able to make a calculation himself, and figure out a theoretical energy maximum ?

It is amazing that Ducharme's straightforward claims should create so much misunderstanding. Let me restate his claims:
(1) LB films currently tested 400J/cc => 200J/cc device level with 50% fill factor
(2) same films but with high k nanoparticles => 520J/cc or 260J/cc device level (50% fill factor) expected not tested.

This is consistent with his claims that he can do better than 400J/cc dielectric ED,

These values are very high, but reasonable. They are from very thin films, which allow ultra-high fields at relatively low k. This is the recipe for high ED.

Eestor say very little, but we know what they have is nothing like Ducharme. His results have NO RELEVANCE for Eestor. They are understandable given current physics.

In fact we know Eestor dielectric has k=22500 at 0V and that the operating field is around 350V/um These two facts mean that (acording to conventional physics) it won't work. Ducharme's work is all about X10 field and /1000 k.

The fact that some Eestor believers hunt around for anything regardless of whether it is relevant to Eestor indicates the high level of speculation necessary to be an eestor believer. Nothing wrong with that, but whereas Daniel's ideas are at least attempting to explain what IS known about Eestor - imagining link with Ducharme work is even more farfetched.

Daniel's ideas break on one of two issues:
Either - they invoke IBLC effect in situations where the barriers have unreasonably high fields (basically, as all reserchers know and is obvious from first principles, IBLC is not a route to high ED).
Or - they suppose configurations of charges which cannot be generated from the known external field

Best wishes, Tom

ee-tom, it was not my intention to link Ducharme's work with the EESTOR one (assuming there is one !).
I just would like a clear answer to a simple question:
What could be the theoretical limit of ED in a plain parallel plates/dielectric capacitor ?
Despite you, zawy and some others did very simple calculations with extremely generous assumptions, you got results wich don't match very well experimental results.

But you made an elementary calculation, which resulted in your absolute max limit to energy storage.
The only assumption you did was the ionic number of the moving charge within the lattice (50 if I well remember), which itself was a very generous number; yet, under such conditions the calculated limit was 250J/cc.
Why Ducharme should not be able to make a calculation himself, and figure out a theoretical energy maximum ?

Actually the theoretical limit is on polarisation. You can continue to increase ED by increasing voltage, even after saturation. (Quote from Ducharme above says this). he is quite right, and very precise. What happens is that after saturation k decreases inversely with increasing V. However ED therefore increases linearly with V.

Thus the theoretical ED limit depends on field. When you plug in Eestor's field you get one result. Ducharme's much higher fields give you a different result. Of course, his material is much lower k, and has lower polarisation than BaTiO3 at breakdown.

For BaTiO3, once you exceed the max theoretical polarisation it breaks down. (think about it). Other materials with much lower k are not limited in the same way because at breakdown voltage (which is much higher) polarisation is much lower, and the polarisation limit may indeed not be met.

The theoretical limit on ED is (I believe) inversely proportional to k. Low k => high ED theoretical limit.

The highest ED dielectrics so far found all have rlatively low k (100 or less). this is unsurprising!

EE-tom, if that was the case, then adding high K particles as Ducharme intends to do would decrease ED, not increase it. How do you explain it ?

(for those who want clearer numbers stated by Ducharme, have a look at this one: http://physics.unl.edu/directory/ducharme/RESEA... , slide 4)

Christine:

What degree of E/M coupling coefficient were you looking for?

The linked abstract below reports 610 uV per cm*Oersted.

Electrical conduction, dielectric behavior and magnetoelectric effect

Basic wrote:

EE-tom, if that was the case, then adding high K particles as Ducharme intends to do would decrease ED, not increase it. How do you explain it ?

Frankly - I a not convinced at all by the Ducharme high k particles. I don't intend to explain it unless it becomes fact rather than speculation. The real problem is that the best ED films are very thin and hardly have room for embedded particles. But in any case the claimed effect is small +50% (?). I think he added this because the addition of nanoscale ceramic filler to improve properties is a standard technique and worth trying.

Ducharme is doing a lot of work on nanoscale composites - and puts ferrorelectric polymer particles into polymer films for high k (k ~ 100). The only ED results he has obtained which are good are the 1nm LB deposited polymer films.. If anyone has anything else relating to ED, rather than high k, please post it!

Bottom line. The nanscale stuff has the potential (in principle0 to provide much higher ED - maybe 400J/cc - through hacing a very high surface area density. It is the same principle (though a completely different formulation) that DL capacitors work on.

This is good stuff, but completely irrelevant to Eestor which clearly is not engaged with any such technology.

Tom

Would not EEStor have very high (surface) area, if we were talking about the surface area of the alumina coating?

Here is a nice paper from a masters student at Kansas State.
Lots of diagrams and "simple" explanations.

https://krex.k-state.edu/dspace/bitstream/2097/...