cross-posted from: https://sopuli.xyz/post/1726805
RMIT engineers say they’ve tripled the energy density of cheap, rechargeable, recyclable proton flow batteries, which can now challenge commercially available lithium-ion batteries for capacity with a specific energy density of 245 Wh/kg.
This is such a puzzle, thank you. :)
I checked Sci-Hub - no matches for “proton battery”, neither for “hydrogen flow battery”.
Falling back on chemistry - I recalled that “dissolving a concentrated acid in water should be done with care”. It is exothermic, water may suddenly boil and splash acid all over the careless chemist.
By definition, acids are substances that can easily give protons (hydrogen ions) to other chemicals. A classic reaction would be acid + base = salt + water (acid gives the H and base gives the OH, so we get H2O), the other components of the acid and base form the salt.
If there is only water on the other side, the reaction is acid giving protons to water. Which acid? How many protons? Those questions determine the amount of power available. And of course - how to control the reaction and extract electrical power?
Browsing Wikipedia, I came across two pages: protonation and deprotonation… and a sample reaction with sulphuric acid:
H2SO4 + H2O ⇌ H3O+ + HSO−
…but found no reference to electricity production, though potential / voltage is obviously available when ions are being created and transfered.
Then, finally I found the RMIT press release:
https://www.rmit.edu.au/news/all-news/2018/mar/all-power-to-the-proton
Some pickings:
The working prototype proton battery uses a carbon electrode as a hydrogen store, coupled with a reversible fuel cell to produce electricity.
It’s the carbon electrode plus protons from water that give the proton battery it’s environmental, energy and potential economic edge, says lead researcher Professor John Andrews.
During charging, the carbon in the electrode bonds with protons generated by splitting water with the help of electrons from the power supply. The protons are released again and pass back through the reversible fuel cell to form water with oxygen from air to generate power. Unlike fossil fuels, the carbon does not burn or cause emissions in the process.
The researchers’ experiments showed that their small proton battery, with an active inside surface area of only 5.5 square centimetres (smaller than a 20 cent coin), was already able to store as much energy per unit mass as commercially-available lithium ion batteries. This was before the battery had been optimised.
“Future work will now focus on further improving performance and energy density through use of atomically-thin layered carbon-based materials such as graphene, with the target of a proton battery that is truly competitive with lithium ion batteries firmly in sight,” Andrews said.
DUDE Thank you!
This was super interesting to read.
Really gives me extra hope that this isn’t another vaporware battery technology.
Perhaps the end of excessive lithium mining is in sight!
Really gives me extra hope that this isn’t another vaporware battery technology.
I’ll take it with a grain of salt:
- From the summary I didn’t see if the energy density is a cell level value or a system level value. We have to compare system level energy densities.
- Also energy density isn’t the only thing lithium ion batteries are good at. Firstly, if the cell at its core is a reversible fuel cell with nafion membrane, the dynamics of the cell will be comparable to PEM fuel cells. Lithium-ion batteries can deliver full power instantly without an issue. With PEM fuel cells you have to be more careful: it’s possible to flood the membrane with water or dry it up if you change power too quickly, which is why their response time (time from set point change to actual delivery of full power) is usually limited to about one minute. Secondly, how good or bad is the calendric and cyclic aging and recyclability of the new battery? Lithium-ion has come a long way concerning lifetime - recyclability not yet, sadly.
- With Sodium-ion batteries there’s another, more mature and similarly environmentally-friendly technology already on the market. And while I wouldn’t have thought that it made sense, chinese manufacturer CATL already has built Sodium-ion batteries for cars, and (sadly) that’s the far more important market for batteries compared to stationary ones.
What’s the reactions? Proton battery sounds like a media-friendly name for a hydrogen fuel cell?
Is it a H fuel cell?
It seems to be a hydrogen fuel cell with an integrated hydrogen atom store made of carbon, capable of absorbing 1% of its own weight in hydrogen.
This seems a little, but a mass unit of hydrogen contains a lot of molecules, so a lot of chemical energy (it is the lightest element after all). For example, 1 kilogram of hydrogen is 12 cubic meters at room temperature, so 1 gram is 12 liters - enough to do a lot of work, if reacted right.
https://newatlas.com/energy/rmit-proton-battery-energy-density/
Proton battery is in reference to hydrogen having a single proton, so proton battery.
According to the source, it’s different in that it stores the hydrogen before it combines to H2, reducing energy waste to the point that it’s feasible to treat it as rechargeable instead of single-use. Lithium equivalent instead of alkaline.
https://newatlas.com/energy/rmit-proton-battery-energy-density/
I would love to see a breakdown of the chemistry behind this technology
Here’s the real source
https://newatlas.com/energy/rmit-proton-battery-energy-density/
Thank you, the drawing is especially helpful. And apparently, the guys are running little fans off their prototype.
Is there a ELI5?
Electricity flows when there is a voltage difference, ie a more positive side and a more negative side that wants to equal itself out.
This battery uses protons (positive charge) to make a voltage difference.
When the protons flow from one side to the other, electricity is generated.
That’s the best I can do I’m afraid.
I’ll try too.
Water can be split with electricity into hydrogen and oxygen atoms, which quickly combine into hydrogen and oxygen gas molecules.
This battery stores energy by using an acid environment to preserve the hydrogen atoms as single and electrically charged ions (weakly combining them with opposite-charge ions from an acid) and uses voltage to attract them into a carbon storage medium, where they de-ionize with the help of electrons from a wire and get deposited in porous carbon as single hydrogen atoms.
Meanwhile, oxygen is formed on the other electrode, far across a membrane. The oxygen cannot come across the membrane and combine with the hydrogen or carbon. Oxygen atoms react among themselves and form oxygen gas molecules.
When time comes to discharge, voltage across the terminals is removed and a load with resistance is installed. Hydrogen atoms stored in carbon give away their electrons, which flow across the wire (peforming work at the load) and ionize oxygen atoms on the other side. This creates a voltage gradient which attracts hydrogen ions to leave the carbon substrate and travel across the medium (acid conductor and membrane) to join with the oxygen ions and form water.
