Egregoros

Okay so these are lithium-air batteries, they pull oxygen from the air so they don't need to carry as much weight. Presumably they're heavier when discharged because they're carrying a bunch of oxygen with them.

The problem is impurities in the air poison the chemistry. So the challenge is getting the air perfect.

Currently there has been a lab demonstration of a 1.2kwh/kg battery with 1000 cycles of lifespan.

12kwh/kg is really just a theoretical maximum for the chemistry.

CATL is saying "this is the future", and since they're the biggest battery maker in ... the world (?) ... that probably means there's going to be a whole lot of R&D pushed at this.

So 12kwh/kg has not actually been shown by anyone, but the way battery density competition has been going so far, we should expect that batteries will cross over the 1kw/kg line in the decade. And given they're about 0.3 now, that's a big improvement already. Enough for short haul aviation.

By about 3 or 4 kw/kg, they're going to be competitive with jet fuel given the losses of a jet engine. At this point there will really be no reason not to electrify aircraft since fuel is dominant in the cost of flight.

I wouldn't be so sure.

First, CATL is a Chinese activity, well-known across industry to be fueled with the end products of industrial espionage- I wouldn't trust their shit to power a flashlight.
Second, even this group openly concedes that 12kWh/kg is purely theoretical at this point, as their current prototype arrays are only doing a tenth of this projected performance. They have a long way to go.
Third, hype is all good with a proven product that's market-ready, but when false hype on YT by third-party fanboys & influencers flood the space, it does far more harm to any advances in the state of the art than it does good.

https://interestingengineering.com/energy/catl-12000-wh-kg-lithium-air-ev-battery

What I'd like to do is create a sink for consuming solar energy in the summer. Take charcoal made from hay -> generate methanol and store it.

One interesting reaction you can do with methanol is this thing: https://en.wikipedia.org/wiki/Gas_to_liquids#Methanol_to_gasoline_(MTG)_and_methanol_to_olefins

It generates a bunch of heat, so you can run that reaction in the winter and heat the house with it, and the output is *surprisingly* similar to 87 octane gas, given it doesn't involve any kind of fractional distillation.

>Aluminum based nanogalvanic alloys
>alloy powders have also been considered as an alternative energy source for batteries (coupled with fuel cells). Demonstrated to produce 1000 ml. of hydrogen gas per gram of aluminum in less than 1 minute and 1340 ml—100% of the theoretical yield at 295 K and 1 atm.—in 3 minutes without the need for hazardous or costly materials, or additional processes. Approximately double rate of reaction in urine.

Basically can make a fuel pack from aluminum dust made from machining byproduct. It is very good for creating hydrogen. Since hydrogen fuel cells produce water, it could feed itself and not need much. Or a drone could land and open its hatch and passively gain water when rain hits it and start the reaction.

The problem for making methanol from hay or woodchips is not intractable, it's just that the way that is known to work is annoying.

A round bail might have 200kg of carbon, if you could turn that ALL into methanol (CH3OH) that would make you about 533kg (178 gallons) of methanol - by adding 66.7kg of hydrogen and rest of oxygen since methanol has an O.

Hydrogen has 33.3 kwh/kg of chemical energy, and electrolysis cells are about 70% efficiency, so you would use about 3173 kwh of electrical energy in order to make that hydrogen.

The resulting 533kg of methanol has 2945kwh of chemical energy. 200kg of carbon has 1820kwh, so 1820 + 3173 - 2945 -> 2048kwh of loss in the methanol process because it generates heat.

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Now the problem is that a bail of hay is not pure carbon, it's a whole bunch of tars and contaminants, and any contamination of the methanol catalyst is going to put a fast end to that process.

You can make it into pure carbon by heating it and driving off the tars, i.e. charcoal kilning, but you lose carbon in the process. But even once you have pure(ish) carbon, you still have a problem because carbon is a solid - you need carbon dioxide and/or carbon monoxide to make methanol.

Again, you could burn the carbon, but that is a massively lossy proposition. All of your 1820kwh that was to be contributed by the carbon goes away because you've just burned the carbon and made heat - which you can't really re-use in the process.

If you burn the carbon in a steam environment, it will rob oxygen from the water and output CO2 and hydrogen, thus re-capturing some of the energy that was lost from burning it, but you're still making an insane amount of heat.

To add insult to injury, the methanol process needs to run at 100bar (1500psi) so you need to compress that CO2 and H2, so you're gonna need to cool it down a lot. The methanol process also makes more heat, and that needs to be kept at 300C or else you melt your catalyst. The methanol process also makes heat, and you can use that heat to make something like steam - since it's 300C, but the carbon + water -> hydrogen + CO2 reaction needs 900C, so basically you're forced to send in oxygen and burn the carbon - and make more heat.

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So the big question is: Is there any way to do carbon + water -> hydrogen + CO2 in a cold (<300C) environment, by using electricity and/or catalysts to drive the process?

If the answer is yes, then we can go from 3 big lossy heat-generating events, down to only 2 (charcoal kilning and methanol reaction)...