This is really brilliant. They cycle between two chemical species that are thermodynamically very stable in our atmosphere, solid MnO2 and Mn2+. This is very smart as a starting point because you don't need to worry about the electrodes slowly rusting away (compare: related work with exotic/expensive/unstable rare earth oxides)
Also this redox couple charges at 1.6 V so oxygen production (which is bad in a cell that also evolves hydrogen) does not really happen (this takes 2.0 V or so)
If I recall correctly, that one was about developing a better filament. I believe the winner was carbonized bamboo fibers. And the filament was the only part of Edison's initial bulb patent that proved to be novel on later examination.
The most lasting contribution Edison made to the light bulb was the screw-in base, with one contact at the bottom and the other in the shell. But even then, there were a lot of alternative designs, as Edison was a real ass when it came to licensing.
But he didn't brute-force far enough to develop the tungsten filament, did he?
>Cui estimated that, given the water-based battery’s expected lifespan, it would cost a penny to store enough electricity to power a 100-watt lightbulb for twelve hours.
Oh dear, I hate university news "journalism" with a passion. For the life of me I cannot understand why they feel the need to dumb down parts of the content while other parts remain decidedly technical. Is it to have something that laymen can quote? In this example, it's not clear how long the storage would be, but presumably overnight? It would make much more sense to compare the expected price to existing solutions, and/or the current price of electricity.
Amortized price is what everybody uses, for every type of power plant. You get financing, and charge an amount that gives you a reasonable profit over the expected life of the plant. You don't charge extra at the beginning. Storage facilities are no different.
Yes, but adding a penny per kWh to the price of electricity is no big deal. Prices in the continental U.S. range from about five to fifteen cents per kWh.
I don't know about this. Countless times researchers discover the next battery so much better than the current state-of-the-art being deployed, only to find out they just can't scale it. New battery technology is really hard.
Yes. Surface chemistry ("nanotechnology") seems to attract this sort of hype.
"The prototype manganese-hydrogen battery, reported April 30 in Nature Energy, stands just three inches tall and generates a mere 20 milliwatt hours of electricity ... The researchers are confident they can scale up this table-top technology..."
That is a really puny battery. It's 1/10th the energy capacity of a typical watch/hearing aid battery, which is about as small as you can buy retail. And it's 3 inches tall. So system energy density is currently something like 0.001 of commercial batteries.
They should have scaled it up a bit more before turning on the hype machine. It's embarrassing to see this out of Stanford.
On that note, does anyone have any idea how it might compare to Peter Allen's open source Iron Battery project? I know the latter is in a very early stage, but maybe there is already a theoretical limit that can be predicted given the properties of manganese and iron.
Could someone ELI5 how the recharge cycle works? On charging it evolves H2 gas; how does that get put back on recharge?
This is very much NOT explained by the paragraph,
> The researchers did this by re-attaching their power source to the depleted prototype, this time with the goal of inducing the manganese dioxide particles clinging to the electrode to combine with water, replenishing the manganese sulfate salt. Once this salt was restored, incoming electrons became surplus, and excess power could bubble off as hydrogen gas, in a process that can be repeated again and again and again.
In the modern sense of the word, this is not a battery. It is a device that cracks water into hydrogen, which can then be fed into a fuel cell. Presumably, it consumes distilled water, which is why it is targeting utility scale storage and not home installations.
The work sounds interesting, but the article is painfully written.
Lead acid batteries produce hydrogen too. I think the insight is that this can’t produce electricity directly, so the chemistry can be much more stable.
The paper, linked below (thanks xelxebar) would beg to differ, it says
> we report a rechargeable manganese–hydrogen battery, where the cathode is cycled between soluble Mn2+ and solid MnO2 with a two-electron reaction, and the anode is cycled between H2 gas and H2O through well-known catalytic reactions of hydrogen evolution and oxidation.
They give an equation for the cell operation as,
Mn2+ + 2H2O ↔ MnO2 + 2H+ + H2
Let me try that with _sub_ and ^sup^, does HN support that?
Mn2^+^ + 2H_2_O ↔ MnO_2_ + 2H^+^ + H_2_
Anyway, that double-ended arrow says that you can read it from right to left, i.e. evolved H_2_ gets back into (or stays in?) the solution to react with the O_2_ from the magnesium oxide to make water. Quote,
> During discharge of the battery, the uniform layer of as-deposited MnO2 on the cathode is dissolved back to soluble Mn2+ electrolyte and H2 is oxidized on the anode.
This puzzled me also. Perhaps it's been kicked down the road as an engineering problem and we'd end up with a hydrogen extraction system which is responsible for that part. We'd probably need to feed protons back in though...
I worked on a similar system when I was finishing my degree. I suspect that, in the next 5-10 years, there will be several versions of this of various sizes ready for deployment.
My guess is that the researchers designed their power source to mimic the behavior of solar and wind farms. The researchers were probably rather specific about these behaviors, but it was too verbose or technical for a news article. Some editor tried to summarize that part of the paper, and that editor failed which is how we got this ridiculous sentence.
Unfortunately, history shows that new battery chemistries are a dime a dozen. It's commercialization and manufacturing at scale that's the real bottleneck. Look at what happened to Aquion, which raised $190 million for their salt water battery:
Research and development, and building out manufacturing infrastructure for something nobody wanted. Looks like they were killed by the falling costs of Lithium Ion. If you plan to be 50% cheaper than Li in 4 years and then 3 years in Li costs have halved, you’re in trouble.
I wonder how safe this will be with hydrogen gas being a part of it. Sounds promising but you’d want it extra safe considering a mini Hindenburg would be attached to your house. Edit. I suppose I read it incorrectly as this is being invented for the utility scale.
Well, any vehicles you park in your garage or in your driveway probably have a lot of stored potential energy that can be released catastrophically under the wrong circumstances too. (this goes for whether it's ICE or electric).
The fact that we generally consider those safe to sleep next to is a testament to safety engineering (and possibly a bit of self delusion).
The wrong circumstances required to catastrophically release all of that energy in an ICE car is pretty extreme, requiring the fuel to atomize and thoroughly mix with air. Otherwise you have a fire, not a bomb. Hydrogen by contrast just needs a spark and then it comes to strongly resemble a bomb. If your hydrogen is under pressure, then simple containment failure can be the “spark” required. Plus, gasoline is easy to store, while hydrogen tends to embrittle materials storing it.
We shouldn’t short sell just how tricky hydrogen can be.
> If your hydrogen is under pressure, then simple containment failure can be the “spark” required.
If the pressure is high enough[1], you don't even need to ignite the hydrogen; pressurized gas storage experiencing catastrophic failure is a bomb. An explosion is rapidly expanding gas. Normally a chemical chain reaction[2] is used to generate that gas, but rupturing high pressure gas storage has very similar effects.
Storing a lot of energy in a small space (high energy density) always includes the risk of that energy being released.
> We shouldn’t short sell just how tricky hydrogen can be.
Working with hydrogen directly is really problematic. However, an easy way to solves most of those problems is stabilizing the hydrogen by attaching it to a chain of carbon atoms.
[1] The storage pressure probably is high enough or the design would have used much cheaper low pressure parts.
[2] e.g. the common high explosives that store lots of single-bonded nitrogen as a solid and rapidly chain react into triple-bonded N2 gas and a lot of energy
Gasoline evaporates under most normal conditions when exposed to air. Fiel soaked rags have been known to spontaneously ignite in garages.
I think what you're describing is the decades of safety advances we've had in ICE engine design that allow for safe fuel storage.
I'm not trying to say that storing hydrogen is easy, I'm just saying that there's probably a significant amount of things we can do to bring the hazard level down, and there would be a real push for more work on those things if we were routinely using these units at our houses.
That is, we would also view the proximity and operation of early model ICE engines to be too hazardous. We've come a long way since then.
Yes, gasoline will burn easily can auto-ignite in common household conditions. I've had the "fun" of running for the garden hose after a roommate made a similar mistake with paper towels soaked with some type of cleaning solution and wiped up engine oil. Fortunately we were able to put out the fire with only minor damage (mostly smoke) to the garage.
However, that's only a fire that will burn[1] at a rate roughly proportional to hows quickly it can mix with oxygen (that can be very fast* in some situations). Getting gasoline to act like a bomb and release it's energy at once[2] requires fairly specific conditions.
Yeah, I think that gasoline will just evaporate on a rag. the spontaneous combustion requires something like linseed oil that generates a lot of heat when drying(exothermic) and left alone on a rag.
With adequate seals this is no more dangerous than existing chemical energy storage, such as gasoline and natural gas.
The researchers state (in the paper itself) that they carefully control the charging voltage to avoid oxygen production in the same cell. Oxygen and hydrogen in the same device is dangerous, only hydrogen not so much.
Yes, but if you’re only storing it <24h to smooth out your daily power generation curve that shouldn’t be too much of a problem. It’s only really an issue if you’re storing it for weeks or more.
Of course, but for short term storage the percentage loss should be small relative to other losses in the system.
Lets say on each storage and recovery cycle over 24h I'm losing 10% of the stored energy from various losses each cycle, including 1% of the stored energy from Hydrogen loss. No big deal. Even though I'm losing 1% to hydrogen loss every 24h cycle, it's small relative to other losses per cycle. After many cycles it would still be a small fraction of overall losses.
Conversely if my cycle time is 10 days for one storage and recovery cycle, at 1% hydrogen loss per 24h all of a sudden I'm now losing more from Hydrogen loss than all other losses combined. That's really bad.
We currently put high-temperature, charged lithium in our pants pockets. The technology this is replacing uses lead and sulfuric acid. Hydrogen is probably fine.
I doubt you can remove your pants faster than a lithium cell going skywards, especially since you'll be experience some quite decent panic at your pants being literally on fire.
One of the major complaints when they trialed fuel cell buses in London years ago was that people though the fueling station would blow up ala hindenberg.
Even though this uses Hydrogen, which means small quantity of water, water still a finite resource, it becomes costly every year, specially the one that's drinkable.
This seems like a double sword, solving one side, while it makes other worse.
It does not say if requires potable water or how much of it would be necessary for big batteries. But I imagine potable water would serve for optimal reactions.
Also this redox couple charges at 1.6 V so oxygen production (which is bad in a cell that also evolves hydrogen) does not really happen (this takes 2.0 V or so)
Really exciting stuff.