Energy

Formic acid fuel cell carries hydrogen over infrastructure obstacles

Formic acid fuel cell carries ...
Researchers at EPFLand GRT Group have developed a promising prototype of a formic acid-based fuel cell. From left: Dr. Nordahl Autissier, GRT Group Senior Project manager; Prof Laurenczy, EPFL, Prof Eng. Luca Dal Fabbro, GRT Group CEO.
Researchers at EPFLand GRT Group have developed a promising prototype of a formic acid-based fuel cell. From left: Dr. Nordahl Autissier, GRT Group Senior Project manager; Prof Laurenczy, EPFL, Prof Eng. Luca Dal Fabbro, GRT Group CEO.
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A diagram of how the EPFL team's formic acid fuel cell works
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A diagram of how the EPFL team's formic acid fuel cell works
Researchers at EPFLand GRT Group have developed a promising prototype of a formic acid-based fuel cell. From left: Dr. Nordahl Autissier, GRT Group Senior Project manager; Prof Laurenczy, EPFL, Prof Eng. Luca Dal Fabbro, GRT Group CEO.
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Researchers at EPFLand GRT Group have developed a promising prototype of a formic acid-based fuel cell. From left: Dr. Nordahl Autissier, GRT Group Senior Project manager; Prof Laurenczy, EPFL, Prof Eng. Luca Dal Fabbro, GRT Group CEO.
Gabor Laurenczy, a researcher on the team
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Gabor Laurenczy, a researcher on the team

Hydrogen fuel cells have long been floated as a potential platform for zero-emission vehicles, but problems with efficiency and storage have put up some roadblocks. Rather than using hydrogen in its normal gaseous state, a liquid hydrogen carrier called formic acid has been proposed, and now researchers from GRT Group and EPFL have built a prototype of a formic acid-based fuel cell.

The uptake for hydrogen fuel cells, both in vehicles and larger industrial uses, has been slow. It's difficult to set up the infrastructure to store and transport the gas, since it needs to be stored under high pressure and can't use the same piping as natural gas. Its fairly low energy density doesn't help, either.

Formic acid could be a more practical solution. It's the simplest combination of hydrogen and carbon dioxide and exists as a liquid under normal conditions, meaning it could slot into existing infrastructure more readily than hydrogen gas. Plus, because it's already widely used in agriculture and industry, the production infrastructure is already in place, and it could soon be made from CO2 using solar power.

Not only does formic acid make hydrogen easier to store and transport, it's a very efficient hydrogen carrier, with 1 L (0.3 gal) of formic acid carrying 590 L (156 gal) of hydrogen. That means hydrogen could be stored in a liquid form, pumped into a device to extract it as a gas, and then fed into a conventional hydrogen fuel cell. Last year, TU Eindhoven students developed just such a system that could be towed behind a bus, feeding hydrogen into its fuel cell to extend the vehicle's range.

A diagram of how the EPFL team's formic acid fuel cell works
A diagram of how the EPFL team's formic acid fuel cell works

The device works on a similar design. Formic acid is stored until needed, then pumped into a hydrogen reformer (HYFORM). Here, a ruthenium-based catalyst turns the liquid into CO2 and hydrogen gases, which is then fed into a proton-exchange membrane fuel cell (PEMFC) to produce electricity. Water and CO2 are produced as waste products, but the team says the latter can be captured and recycled through the system, by hydrogenating the gas to create more formic acid.

In its current form, the HYFORM-PEMFC system can produce 7,000 kWh of electricity every year, boasting a nominal power of 800 W and an electrical efficiency of 45 percent. The team says the fuel cell design has zero carbon dioxide balance, doesn't produce particles or nitrogen oxides, and is completely environmentally friendly if the formic acid is sourced responsibly – either using the CO2 waste from the device or by oxidating biomass.

The system is low maintenance, scalable and doesn't need any external power source, according to the researchers. The ruthenium catalyst is long-lasting and relatively inexpensive, but the team is currently working on an even cheaper alternative.

Sources: EPFL, GRT Group

10 comments
Craig Jennings
Well.... it's cheaper than Platinum ! :D
Mr T
45% efficient. That's a non-starter right there. Add to that the losses of manufacture of the formic acid and transportation of acid to fuelling outlets and you are down to maybe 25% efficiency (just a guess). This doesn't achieve much at all, and is woefully less efficient than charging batteries from the grid. Same old fuel cell problems really.
KenLM
I'd really like to see a detailed comparison between this and ammonia as a storage means for hydrogen. See https://newatlas.com/membrane-hydrogen-ammonia-distribution-csiro/49509/ The advantage of both of these is being able to utilise a lot of existing infrastructure in much the same way as we currently fill our cars with fuel.
Jim B
@KenLM - you're right that ammonia is probably a much better way of storing hydrogen than fomic acid or some other form that requires a carbon feedstock. Getting CO2 from air would be expensive/difficult as there is so little of it, whereas Nitrogen is abundant. Newatlas is off the mark about producing any store of hydrogen from solar power. If you are running a chemical plant you want a constant power source, not an intermittent weather based one. Emissions free thermochemical production of hydrogen could be possible with some of the 4th generation nuclear plants with high output temperatures such as molten salt reactors or gas cooled reactors.
Rumata
There is no reason to complicate Hydrogen Economy by using formic or ammonia, since the pressurized hydrogen storage techhnology is already safe, economical, and mature. We just need cheaper and more efficient hydrolizers and fuel cells. Guys, keep it simple.
rjpaur
How does this version of formic acid fuel cells differ from the ones developed some 20 years ago by Rich Masel and his group at the Univ of Illinois-UC?
Vernon Miles Kerr
Who would'a thunk? Fuel cells powered by ant venom! "Most ants spray or inject a venom, the main constituent of which is formic acid only in the case of subfamily Formicinae." https://en.wikipedia.org/wiki/Ant_venom
fen
@Mr T "This doesn't achieve much at all, and is woefully less efficient than charging batteries from the grid." But the grid goes off during the snow, and during the summer, and during the floods, and when everyone watches world cup. But my local filling station would always have a tank full of formic acid. Think about battery replacements. A hydrogen tank never needs to be replaced. If we have to waste energy to pool large amounts of green energy all around the country, then we should waste the energy to do it. The goal isnt to hit 100% efficacy its to get 100% green. Batteries can never get any greener, hydrogen can do nothing but get greener.
KenLM
@Jim B Thanks. However I'm not so sure about the need for continuous production. Using a largely passively managed system solar cells (and/or wind) could produce a lot of ammonia but so long as there is a reasonable storage buffer, the variable rate of production need not be a problem.. A disadvantage of current battery technology is that it takes a considerable time to charge a battery powered vehicle, during which time it is immobilised. In time technology will allow faster charging but this will require considerable infrastructure to supply the necessary current, which in remote areas could be problematic (I'm Australian). However those remote areas have plenty of storage tanks that can easily be filled with ammonia for rapidly pumping into vehicles. Vehicles that are in almost constant use or undertaking long journeys could particularly benefit from rapid refueling via this type of system. I understand that both Toyota and Hyundai are trialling ammonia/hydrogen fuel cell cars in Australia.
ljaques
Buses can run on 800Wh while towing a ton and a half of ant juice? Interesting. This I gotta see. Well, it's a start.