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[*] posted on 1-1-2010 at 04:00
Hydrogen ignited in Ozone gas


We all have seen a test-tube of hydrogen popping when ignited by a splint demonstrating the explosive nature of hydrogen igniting in oxygen. Has anyone here tried igniting hydrogen in ozone O3 gas? Would you get a bigger bang? Would water be the result of would you get hydrogen peroxide?
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[*] posted on 1-1-2010 at 06:36


Water would still be the result of the reaction. I indeed expect a bigger bang, I can even imagine that no spark is needed to ignite a mix of pure ozone and hydrogen gas, but I am not sure about that.



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[*] posted on 1-1-2010 at 06:53


I wouldn't expect a bigger bang because it's essentially the same reaction. . .
The instability of O3 would probably cause ignition of H2 by contact.
Is it true, though, that a H2/O2 mixture won't explode by spark unless a trace of H2O is also present?

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[*] posted on 1-1-2010 at 09:16


I read that by itself Ozone is an explosive allotrope, by explosive I guess they mean unstable. I would have thought that adding hydrogen would make a bigger bang.

H2 + O3 = H2O + O1 (free radical) ??

[Edited on 1-1-2010 by D4RR3N]
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[*] posted on 1-1-2010 at 10:04


The additional energy you get is due to ozone breaking down to oxygen. Nothing more. It may proceed faster, for instance O3 might break into 2-3 radicals, thus propagating the reaction faster than with O2.

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[*] posted on 1-1-2010 at 11:14


I was thinking it might be a good fuel to run an engine on ;-)
If the reaction did propagate faster that would result in a bigger bang.

[Edited on 1-1-2010 by D4RR3N]
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[*] posted on 1-1-2010 at 12:20


Ozone is not a fuel, it's an oxidiser. . .
As for using it in an engine, if it were advantageous I'm sure we'd have heard about it.
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[*] posted on 1-1-2010 at 12:51


Ozone wouldn't be easy to use in an (internal combustion) engine. Besides attacking most plastics and rubbers (used in tubing, control valves, etc.) it's unstable as a liquid or compressed. Piston engines most definitely don't want a detonation or uncontrolled fast combustion: that cracks pistons and connecting rods, bursts piston rings, and burns valves. "Octane number" for gasoline is a rating for how controlled and evenly the fuel combusts. The higher the octane number, the smoother it burns.

Racers have used nitrous oxide (N2O) occasionally to give their engines more oxygen per volume to increase power output because it will burn twice as much fuel per stroke as air. N2O is easily stored as a liquid, doesn't detonate on contact with combustibles, isn't toxic in moderate amounts, and is otherwise generally benign in comparison to ozone.
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[*] posted on 1-1-2010 at 16:07


You wouldn't need to store the Ozone so you don't need to worry about its being unstable or about it attacking plastics due to its oxidising ability. Ozone can be made by passing air through plates connected to a high voltage, the smell you get near a photocopying machine is Ozone produced by the EHT.
Hydrogen produced by electrolysis of water could be stored in metal hydride.
Instead of combustion the hydrogen with air the air could be sucked in, passed over an EHT converting it to O3 rich mix and then ignited with the H2 in the engine (no storage needed and no need to worry about the instability of O3)... also a piston engine is not the only type engine available.



[Edited on 2-1-2010 by D4RR3N]

[Edited on 2-1-2010 by D4RR3N]
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[*] posted on 1-1-2010 at 16:56


The efficiency of making O3 from O2 suck pond scum, a large percentage of the energy is wasted. That's energy you have to provide from somewhere. On top of that the air (or O2 which gives better yields) should be clean, dry, and cool, for best yields; that adds complexity, weight, and power losses in driving the filtering and what not.

If you ran the numbers I think you'd find you'd come out ahead just installing a slightly larger engine and fuel tank.

BTW - current methods of storging hydrogen are pretty poor, the volumetric energy density leaves much to be desired - big tanks are needed. You come out better storing hydrogen as ammonia, either as the liquid under moderate pressure or as its complexes with MgCl2, and burning the ammonia mixed with 5% to 10% hydrocarbon as fuel. Those storage methods result in about 50% more hydrogen per unit volume than you get with liquid H2. Methane gives even denser storage, near twice LH2, but is harder to store than NH3 and more like H2 in that aspect.
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[*] posted on 1-1-2010 at 17:33


Well the point I was making was more about what would come out of the exhaust pipe (considering all the talk about us destroying our environment). I'm aware you could just use a bigger tank and engine but increased power was not what I was considering but an environment friendly fuel was.
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[*] posted on 1-1-2010 at 18:14


hmmm ... exactly what coming out of the exhaust pipe to you think your scheme will help with? Define "environment friendly fuel"

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[*] posted on 1-1-2010 at 18:43


Steam/water droplets would come out of the exhaust, zero effect in terms of greenhouse gases.
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[*] posted on 1-1-2010 at 18:52


You'd still get oxides of nitrogen unless you carried an oxygen concentrator and fed the engine with 95% O2. More weight and complexity :mad: Combustion of hydrogen is HOT.
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[*] posted on 1-1-2010 at 19:34


Quote: Originally posted by D4RR3N  
Steam/water droplets would come out of the exhaust, zero effect in terms of greenhouse gases.

Ah, but where does the energy to make the H2 and O3 come from?

Electrolysis efficiency runs 60 to 75 percent, theory says 80 to 90% best unreachable case. 1 kWh worth of H2 takes 1,4 kWh of electricity. When making H2 from fossil fuels its a bit better, 80% or so.

The energy needed to store H2 is equal to 1/4 to 1/3 the energy, so to store 1 kWh energy as H2 you need to expend at least an addition quarter kWh.

Now to use the energy stashed away in the hydrogen. Heat engines in that size run 25 to 35 percent efficient, that is for every kWh tucked away as chemical energy in H2, you will get 250 to 350 Wh as useful work. The power train loses an additional almost 6% of the input energy, 60 Wh out of the kWh. So each kWh stored in H2 will deliver 190 to 290 Wh to the wheels.

Go with a PEM fuel cell, the sort generally chosen for H2 automotive designs and the results are a bit better. PEM fuel cell systems run 40 to 45 percent efficient, and can eliminate the power train but using hub or wheel motors. Say 300 to 400 Wh to the wheels for every kWh of H2 consumed.

So total up the entire chain and get:

H2 burning heat engine needs 7,5 kWh input for every kWh to the wheels, ~13% efficiency, not very far from a conventional car.

H2-PEM fuel cell needs 4,7 kWh input for every kWh to the wheels, ~21% efficiency

A pure battery-electric vehicle with current design electronics puts 90-95 percent of consumed power into the batteries, delivers 90-95 percent to the motors, which in turn deliver 80 to 90 percent to the wheels. Say 70% efficiency or 1,4 kWh input for each kWh at the wheels.

A modern coal fired power plant is around 40% efficient. The latest combined cycle gas turbine system run 55-60 percent. So if you burned fossil fuels to make the electricity for BEVs, you'd see 28% to 39% efficiency for the entire system, fuel to wheels; getting close to three times current or H2 burning ICE, or twice a H2-fuel cell system. The H2 ICE will be as responsable for almost as much CO2 generation as conventional automobiles, and for roughly 3X the BEV; if you use some other source of electricty to make the H2 then that source can be used for the BEV as well, retaining the 3X relationship.

If you want to continue to use ICE driven vehicles, then using a mix of 90% NH3 + 10% C3H8 will reduce CO2 production by 90% and give lower NOx output as well; all without the complexities of the H2 infrastructure as simple low pressure fuel tanks can be used. For North America there is a sizeable ammonia pipeline network already in place in the central regions.


You say "but I want to use O3 in the engine too" Fine, looks like around 820 Wh per mole of O2 using air(*). Thats filtered, hydrocarbon-free, -40 dew point air no warming than 20 C. The additional energy will not exceed that for 2 O3 > 3 O2, I'll leave it to you to calculate how much of that 820 Wh ends up as useful work, and how much power is needed to prepare the air as well as haul around the extra mass of the O3 generation system.


(*) see http://www.lenntech.com/library/ozone/generation/ozone-gener... for numbers on ozone production.


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[*] posted on 1-1-2010 at 20:18


I read somewhere that 30% ozone (70% O2) has been used as a cryogenic liquid oxidizer (with hydrogen I think) in some experimental rockets. Higher concentrations are unstable and likely to explode on their own accord. The performance of the ozone blend was only slightly if any better than pure liquid oxygen, making it completely useless considering how much more energy it takes to produce. Not only that but O2 is more volatile than O3, and after shutdown the residual material in the lines would concentrate as it evaporated, eventually resulting in an explosion if it was not fully purged.

As has been said, all known methods of ozone production are miserably inefficient, making it completely useless as an oxidizer or combustion aid in any type of engine. There are numerous schemes for recovering waste energy in an engine that are far more efficient. Even if ozone could be produced efficiently it isn't that much better than regular oxygen especially considering how corrosive and explosive it is in high enough concentrations to make a difference.


Quote:

If you want to continue to use ICE driven vehicles, then using a mix of 90% NH3 + 10% C3H8 will reduce CO2 production by 90% and give lower NOx output as well; all without the complexities of the H2 infrastructure as simple low pressure fuel tanks can be used. For North America there is a sizeable ammonia pipeline network already in place in the central regions.


Unfortunately all that ammonia is produced using hydrogen obtained from methane steam reforming, resulting in just as much CO2 emission. We need a better way of producing hydrogen before we can really use ammonia or hydrogen itself as a fuel.

[Edited on 2-1-2010 by kilowatt]




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[*] posted on 2-1-2010 at 04:53


If you think about the energy used to drill a hole in the ground put a pipe down to extract gas or oil, then process that so that it can be used for a fuel in a car engine.

Compare that to water which is abundant and requires little processing apart from filtering it to prepare it to be split via solar energy. I think that those massive solar collector projects in Australia and America will probably be the means to produce hydrogen from water in large quantity in the future. Transport of hydrogen is a problem though which is why I think something like metal hydride or a better system will have to be used.

If this rocket experiment has taken place and liquid Ozone was ignited with liquid hydrogen without any dramatic increase in thrust then you are correct, it is pointless to use Ozone!.....I never heard of this rocked before and my initial question was just an idea to increase the potency of hydrogen as a fuel for cars.

Here is the thing rocket scientists are smart guys! Why did a team of rocket scientists even attempt this? A rocket is an expensive thing surely they must have calculated the result before they spent the money on the experimental rocket?
They must have at least amused it was going to produce greater thrust?

[Edited on 2-1-2010 by D4RR3N]
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[*] posted on 2-1-2010 at 05:56


I read this statment at:

http://www.time.com/time/magazine/article/0,9171,868054,00.h...


When chemists dream their fanciest dreams, they imagine powering a rocket with liquid hydrogen and liquid ozone (03). This pair is tops for energy. Its reaction has a specific impulse of 373. The specific impulse of the traditional kerosene-oxygen combination is only 249


If this is correct then a mixture of hydrogen gas and Ozone gas would be more potent as a fuel then hydrogen gas and oxygen gas.

[Edited on 2-1-2010 by D4RR3N]
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[*] posted on 2-1-2010 at 10:57


Rockets are special cases, they always have to carry both fuel and oxidiser with them. Most of the mass of propellants must be lifted off the ground for at least a short distance, so the lighter those are the better.Storage is also not of primary concern, given the money that can be spent and support staff allowable, liquid hydrogen is acceptable for rockets but not for your car. The cost of the oxidiser and fuel is not of primary concern, nor is the overall efficiency - what for automobiles is referred to as "well-to-wheels".

Vehicles for everyday use sit surrounded by oxidiser, saving a good deal of energy by not having to carry it around (or generate it in place as for O3). The complexity, volume, and mass of the oxidiser associated apparatus adds to the production and operation costs of the vehicle; making it larger or heavier means more energy is needed to move it.

Hydrogen is a lousy fuel for general purposes. It has low volumetric efficiency, meaning that it takes up a lot of space to store a given amount of energy. It takes a lot of energy to liquefy it or store it as highly compressed gas; if you liquefy it then a significant percentage boils off every day, if you compress it then it tends to diffuse out through tiny leaks or solid metal. Metal hydrides are either quite heavy and generally fairly costly, only a few percent of their mass is hydrogen, or very reactive (LiAlH4), or "need further development" meaning "this might work, if you sink enough money into it and don't mind waiting a decade or two".

From a 2005 report on hydrogen as fuel
Quote:
Currently, the only systems that allow the storage of the DOE targeted 6.5 wt% hydrogen, with the fuel being available at less than 100C are composite cylinders containing gaseous hydrogen and heavily insulated tanks containing liquid hydrogen. Neither of these are considered acceptable for passenger vehicles.


The amount of 'punch' a rocket fuel+oxidiser system has may be of primary importance for that application, but for daily use it is not, what is important is overall cost - complexity and full system efficiency. That's why I gave those numbers for the efficiency of H2 fuel options. A low efficiency system means much more generation capacity is needed, and more generation capacity means more expense in building, maintaining, and replacing that capacity. The well-to-wheel efficiency for H2 is no better than the current fossil fuel burners, if the H2 comes from fossil fuels then it results in just as much CO2 release. If it comes from renewable energy it requires the construction of several times as much generation capacity as alternatives. For typical daily travel BEVs beat H2 fueled cars hands down, and require less infrastructure construction.

And that applies to using ozone, too. If the overall energy cost of making and transporting the O3, even making it in place as that requires pretreatment of the air, exceeds the gains to be had by using the O3, then it's quite possibly a ineffective idea. Given that the extra oomph from O3 is coming from the energy stored in its bonds over that in O2, and that it takes much more energy to make that O3 than is stored in it, using O3 will result in additional energy demands. Again, it can make sense for rockets and other special applications where alternatives are few and costs are not the primary factor, but for day-to-day applications it's wasteful.

If you want to distribute energy then power transmission lines are much more efficient than shipping about hydrogen. Liquid ammonia carries 50% more hydrogen atoms per unit volume that does liquid H2, and liquid ammonia is much easier to store and has much lower losses than does LH2. Other ways of shipping energy as fuel that are much better than elemental hydrogen include elemental Al, Si, B, and Zn.


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[*] posted on 2-1-2010 at 12:40


Electric cars will never become popular as long as a battery is the means of storing the electrical energy, takes far too long to charge up (most people wont be interested in having to plug their car in for over eight hours to charge up).

An air powered car would be probably better then an electric car, especially if using a solid air exchangeable cartridges http://www.youtube.com/watch?v=eY1KNxhd2Zs

How would you make the ammonia gas, not from fossil fuels surely?
Also the nitrogen component in ammonia, how will that react with oxygen. Will it make oxides of nitrogen?

[Edited on 2-1-2010 by D4RR3N]
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[*] posted on 2-1-2010 at 13:33


Rapid charging battery systems are in various stages of development. Charging causes metal to be deposited or generated from discharged compounds in place. This usually changes the volume of the electrode material, causing it eventually to fail. The better control of particle size, protective chemistry and mechanical factors, etc. are steadily improving charge times. When will it be 5 minutes? Demonstrations have been done; there's a -lot- of money at stake.

Improved conductive skeletons for electrodes (carbon nanofibers are a current candidate) are also important because they reduce resistance which means less waste heat while charging. Less heat means less deformation means better battery life.

Will there suddenly be a "wow, 5 minute charging tomorrow"? No. Will there be incremental improvements? Yes, they're constantly taking place. Over the last few years NiMH AA size cells went from 600 mAH to 2400 mAH and above and also went from 16 hour charge times to 45 minute or less. Similar improvements for lithium based cells are happening. Check the LiFePO4 progress, for instance.

Of course, electrical infrastructure to supply 200KWH to each vehicle in 5 minutes each is costly and elaborate. The supply chain for delivering petroleum products is very costly and elaborate, but it was built over 100 years so we don't see it as being a big deal.

For delivery vehicles, buses, etc. which have predictable routes, scheduled times, and centralized garaging the recharge time and infrastructure is much less of a problem. Big bulk buyers of these vehicles will probably be quiet leaders because they can realize good payback and often can get subsidies, etc., to cut their pollution output. Their recharge times can be scheduled to be optimum for electric utilities so that the utility can use the "base load" plant - the cheapest and most efficient - for that service when other demand is low.

One scheme which is not wonderful but applicable right now is battery exchange at a service station. I'm sure there would be horrendous arguments and incompatible batteries for a while, but economic incentives for a standard pack would be huge. Various systems have been tried. It would take (guessing) a 1.5X to 2X increase in
power density to make a Lithium based Prius-size pack something which could be swapped in a minute or two. It might mean using numbers of standardized packs to keep the weight and size low enough for easy handling. It's a -lot- less messy than pumping many gallons of volatile, poisonous, flammable, etc. liquids for refueling.... The packs could be recharged overnight at the station or trucked (just like gasoline is trucked) to recharge points. Ugly? Yes! Feasible? Yes. Cost effective? Good question... it would take 5-10 years to get all the pieces in place.




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[*] posted on 2-1-2010 at 14:28


Yes there is a lot of money at stake with those developing battery powered electric cars but I think they should cut their losses and realise they are barking up the wrong tree. It will never take off, can you imagine the heat generated even if you could charge up a massive battery like that in five minutes! Rapidly charging up the battery and then the large electrical load on the battery with the hub motors running will knacker the battery in no time at all (expensive too!)

The air car can be filled in 3 minutes, is simple and has no expensive parts so is probably better then a battery car.
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[*] posted on 2-1-2010 at 19:39


Compressed air power is a nice idea, but suffers from several problems. The first is low efficiency, using numbers from developers and proponents of the concept a compressed air care is between 1/2 and 1/3 as efficient as a BEV.

The next is range, compressed air at currently practical densities hold less energy per unit volume than do batteries in use today. This means that for a given amount of the vehicle given over to storing power, a compressed air car carries less energy, and uses that in a less efficient motor; range for similar weight vehicles is less for the air car.

As the air expands in the motor, it absorbs heat and drops in temperature. As this results in air colder than ambient, thus is colder than the air pulled in for compressing. This means the air in the motor will occupy less volume that it did originally, a energy loss. To compensate for this the air must be heated. This can be done in multistage motors by having heat exchangers warming the air between stages. Normally this uses ambient air as the heat source, which works fine in hot climates. But in cold climates it is a different story, Prague and Des Moines in winter are not good heat sources. Furthermore, in cool moist maritime climates the heat exchanges can become covered in ice, rendering them ineffective.

As a result several developers of such vehicles ended up adding a fuel burner to heat the air. Such a system uses less fuel than a conventional engine, internal or external, does for the same amount of output power. This is because of the energy stored in the compressed air, the overall efficiency depends on the efficiency of the compression step.

So I have the choice of driving a BEV and on returning home plugging it in to recharge overnight, or using a CAC that costs at least twice as much per km and that requires me to go out away from home into the weather, wait in line at a filling station, fumble around with my currency card, and fill the tank (or instead pay someone to either fill or swap the tank, further raising the operating cost). Makes the compressed air car seem a lot of bother as well as significantly more expensive; but if you're into S&M it just might be for you.

And that is an important point. Everyone assumes that BEVs would be used identically to a typical car of today, thus the refueling time issue. But a BEV can be recharged when you are not driving it, avoiding the need to travel to a filling station. Similarly people can't use current BEVs because of the range limit even though their daily travel distance is much less than the range of the BEV. When this is pointed out various excuses are given, ones I've heard include "we visit Grandmother twice a year and she lives 399 miles away" and "we going camping with friends for a week every year, so we need a SUV to carry everything and travel far enough"

Quote:
Through a series of press releases and demonstrations, a car using energy stored in compressed air produced by a compressor has been suggested as an environmentally friendly vehicle of the future. We analyze the thermodynamic efficiency of a compressed-air car powered by a pneumatic engine and consider the merits of compressed air versus chemical storage of potential energy. Even under highly optimistic assumptions the compressed-air car is significantly less efficient than a battery electric vehicle and produces more greenhouse gas emissions than a conventional gas-powered car with a coal intensive power mix.

From http://www.iop.org/EJ/article/1748-9326/4/4/044011/erl9_4_04... a recent analysis of compressed air vehicle efficiency, full document is freely available.

A slightly more favorable evaluation focusing on just the compression-expansion aspect, and getting about 60-70 percent efficiency, is in this PDF http://www.efcf.com/reports/E14.pdf


From http://www.greencarcongress.com/2009/06/revetec-20090606.htm...

Quote:
That volume of air (.27 m^3, or cubic meter), if expanded isothermally at room temperature, can generate only 12.8 kwh. However, the expansion process is not isothermal, but more like polytropic, emitting very cold air out of the exhaust pipe, so, you can get but ~1/2 of that energy before even considering mechanical losses in the air motor. I don't see how can any USA-street-worthy car run for 40 miles out of 6.5 kwh. (The formula is 100xlnPa/Pb kJ/m^3 of initial gas volume before compression = 100xln300x0.27x300= 100x5.7x0.27x300=46,200 kJ = 46,200kJ/3600= 12.8kwh)

An efficient BEV can do 4 miles/kwh, so 6.5kwh x 4mi/kwh = 26 miles range max. The French "Air Car" can get only 7-10 miles range in real life when demonstrated to reporters.

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[*] posted on 3-1-2010 at 01:00


As for the ammonia, it was meant to illustrate that there are better choices than elemental hydrogen. There are two options

A) Today, Haber-Bosch using H2 produced the same way you would for using H2 as fuel. While there are energy losses in the ammonia plant, the lesser energy cost of storing ammonia, plus the increased convenience of that storage and its greater density of hydrogen, offsets those losses as compared to H2.

B) there are several new ammonia production processes in development. In general these run at much lower pressures than Haber-Bosch, and take steam and N2 as their feedstocks - no separate H2 generation. One process runs at atmospheric pressure, another fairly low pressure looks to be more energy efficient than Haber-Bosch

http://www.energy.iastate.edu/Renewable/ammonia/ammonia/2007...
http://www.springerlink.com/content/05714h07p14p71mw/
http://www.sciencemag.org/cgi/content/abstract/282/5386/98
http://www.reeis.usda.gov/web/crisprojectpages/192890.html

if your H2 fuel is going to use yet-to-be-developed storage means, I'm allowed to refer to processes yet in the labs.
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[*] posted on 3-1-2010 at 07:47


Quote: Originally posted by not_important  
B) there are several new ammonia production processes in development. In general these run at much lower pressures than Haber-Bosch, and take steam and N2 as their feedstocks - no separate H2 generation. One process runs at atmospheric pressure, another fairly low pressure looks to be more energy efficient than Haber-Bosch
Thanks for this. Very interesting.

The solid state technology under development shares a lot with SOFC (solid oxide fuel cells). It's essentially the same subfield of ceramics science to get the materials right. Widespread use of SOFC's is limited by material limitations, principally cost and 600° C operating temperatures. Luckily the technology here requires only a proton ionic conductor, rather than the oxygen ionic conductor required for SOFC. I can't seem to find the relevant patent application, unfortunately. If actually filed in 2007, as stated, it should be published by now.

I did find the Lynntech patent: Electrochemical synthesis of ammonia.
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