
Researchers have developed a water-based battery to store solar and wind energy - nopinsight
https://news.stanford.edu/2018/04/30/new-water-based-battery-offers-large-scale-energy-storage/
======
isoprophlex
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)

Really exciting stuff.

~~~
raverbashing
Makes me wonder why they didn't think of this before or what challenges have
they overcome this time.

~~~
amelius
> Makes me wonder why they didn't think of this before

Because a brute-force search is something only an IT professional can come up
with.

~~~
spodek
“I have not failed. I've just found 10,000 ways that won't work.” ― Thomas A.
Edison

~~~
trisimix
Edison didn't even invent the lightbulb, which is what that quote is
referencing.

~~~
logfromblammo
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?

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svantana
>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.

~~~
DennisP
Well that'd be 1.2 kWh, stored for a penny. Average electricity price in the
U.S. is 10 cents/kWh.

I've often criticized people for ignoring the cost of storage when talking
about wind/solar prices, but at a penny per kWh it's pretty insignificant.

~~~
tajen
But that’s for storage, not production.

~~~
DennisP
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.

------
josecyc
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.

~~~
Animats
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.

~~~
TTPrograms
Utility scale batteries optimize for energy/$, not energy density or weight
etc.

Your comparisons are totally irrelevant.

~~~
vanderZwan
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.

[http://peterallenlab.com/](http://peterallenlab.com/)

[https://www.youtube.com/channel/UC-t9a7XVoH9lDJzhUF2nyHQ](https://www.youtube.com/channel/UC-t9a7XVoH9lDJzhUF2nyHQ)

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fernly
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.

~~~
hedora
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.

~~~
fernly
> ...not a battery.

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.

So, I guess it stays in solution...?

~~~
jwilk
HN formatting capabilities are not great, but you can use Unicode
sub-/superscripts:

Mn₂⁺ + 2H₂O ⇌ MnO₂ + 2H⁺ + H₂

(Shameless plug: I generated the above with
[https://github.com/jwilk/chemiscripts](https://github.com/jwilk/chemiscripts)
.)

------
haZard_OS
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.

------
konschubert
> To mimic how a wind or solar source might feed power into the battery, the
> researchers attached a power source to the prototype.

So, they charged the battery? Why doesn't the article just say that? Does the
intended audience of the article not know what "charging a battery" is?

~~~
thefifthsetpin
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.

------
EdCoffey
There's some more detail on the construction, and what becomes of the hydrogen
(it will be stored in large pressurized steel tanks) here:
[https://cen.acs.org/energy/energy-storage-/New-battery-
serve...](https://cen.acs.org/energy/energy-storage-/New-battery-serve-
grid/96/web/2018/05)

------
8bitsrule
"the researchers are confident they can scale up this table-top technology to
an industrial-grade system"

Oh dear.

------
apsec112
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:

[https://www.greentechmedia.com/articles/read/Aquion-the-
Bill...](https://www.greentechmedia.com/articles/read/Aquion-the-Bill-Gates-
and-Kleiner-Perkins-Funded-Advanced-Battery-Startup#gs.AJ5cTbs)

~~~
wpietri
Ouch. And they later sold for $9.2 million. I sure have some questions about
what they spent the money on.

~~~
simonh
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.

------
tzahola
K...Keep me posted!

I’ve learned not to get too excited by battery research. It was all vaporware
in the past 20 years.

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weaksauce
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.

~~~
kbenson
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).

~~~
dbasedweeb
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.

~~~
kbenson
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.

~~~
NegativeLatency
I was only aware of oil (not gas) soaked rags spontaneously combusting

~~~
weaksauce
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.

------
Tade0
Sound great, but somebody else might have already stolen their lunch:

[https://eosenergystorage.com/](https://eosenergystorage.com/)

This product is, of course, more expensive but at least it's already being
deployed.

------
lm2s
Unrelated: this reminds me of the “2-tier” water dams that also store energy
in the form of water from whatever production source connected to them.

------
syntaxing
I was always under the impression that water has an extremely low energy
density (in 2H2 + O2 form) relative to existing technology?

------
d--b
Can anyone comment about the size of these? How much hydrogen do you need to
store a KWh? And how much manganese solution do you need?

------
Tepix
> it would cost a penny to store enough electricity to power a 100-watt
> lightbulb for twelve hours

Ha, 100 watt lightbulbs do not exist! /s

~~~
protomyth
They still do because some folks need to heat/light the chicken coop or
compressor. /s not withstanding

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Tepix
Given that this battery stores energy as H2, doesn't Hydrogen tend to diffuse
and escape from the battery after a while?

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leibnizwasright
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.

~~~
programbreeding
Does this require potable water though?

~~~
leibnizwasright
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.

