Carbon has a (justifiably) dangerous repute for its position in local weather change.
You have heard we have to scale back our carbon emissions, our carbon footprint, our carbon miles.
That is definitely the case, however that is usually carbon that’s emitted into the environment as carbon dioxide, methane and soot.
Different carbon supplies additionally want a little bit of respect. They are going to be essential to our transition from burning fossil fuels.
Lithium-ion batteries, hydrogen gasoline cells and photo voltaic panels will all assist us scale back our reliance on these previous sources of power — and so they all use carbon supplies.
Let’s discover a number of of the carbon supplies that may enhance inexperienced power expertise.
With out carbon, lithium-ion batteries are inclined to catch fireplace
Lithium-ion batteries are a cornerstone expertise for decarbonisation.
They are going to energy our electrical vehicles and assist buffer renewable power fluctuations within the grid.
However lithium steel reacts violently with air and water, resulting in early lithium-cobalt batteries catching fireplace.
Japanese chemist Akira Yoshino solved this drawback within the Eighties by including carbon to the lithium-cobalt battery.
Particularly, Professor Yoshino added graphite—a type of crystalline carbon. Graphite soaks up lithium steel, forming a steady compound the place, for each six carbon atoms, one lithium atom is saved in ordered arrays between graphite’s layers.
The “lithiated graphite” additionally adjustments coloration from a boring black to a wonderful gold.
If the battery is uncovered to air, the oxygen and water can not as simply get to the lithium, making it secure sufficient to retailer in your pocket.
Professor Yoshino shared the Nobel prize in Chemistry in 2019 for creating lithium-ion batteries as we all know them immediately.
It’s only actually up to now decade that these batteries have began to decarbonize our lives by way of electrical vehicles and in our electrical energy grids.
And whereas lithium-ion batteries seem set to take over the world, there are nonetheless some points that would result in manufacturing bottlenecks.
Many of the graphite utilized in lithium-ion batteries is mined and isn’t pure sufficient for use instantly in batteries. It additionally requires washing in acid to take away contaminating metals, resulting in an environmentally damaging waste stream.
To create another, researchers within the Carbon Group at Curtin College have been engaged on producing graphite for batteries from, for example, development waste.
“We’re in a position to convert polyvinyl chloride, a standard waste materials utilized in plastic piping, into high-quality graphite,” mentioned Jason Fogg, a PhD pupil who research carbon supplies science.
However this waste-derived graphite remains to be extra energy-expensive in contrast with mined graphite.
“The excessive temperatures required are the present problem,” Mr Fogg mentioned.
“You have to warmth the plastic pipe to virtually 3000 levels Celsius, which is half the floor temperature of the Solar, earlier than it converts into graphite.”
Irene Suarez-Martinez, who co-leads the Carbon Group, has been turning to supercomputers to seek out methods to decrease this temperature and, subsequently, make waste-derived graphite cheaper.
How does carbon assist inexperienced hydrogen?
Nations are investing billions in “inexperienced hydrogen” — hydrogen fuel produced with renewable power — which can be utilized as an power retailer.
However there are vanishingly small quantities of naturally occurring hydrogen fuel right here on Earth. It is because hydrogen likes to bond with oxygen to type water.
To make inexperienced hydrogen, electrical power from renewables splits the water molecule into hydrogen and oxygen in a tool known as an electrolyser.
A gasoline cell system can then later recombine the hydrogen fuel and oxygen, offering electrical power on demand—in, say, a hydrogen fuel-cell electrical automotive.
One of many predominant challenges holding hydrogen again as an power supply is the price of the platinum steel wanted in gasoline cells and electrolysers to let the reactions happen.
However because of the shortage of platinum within the earth’s crust, it’s horrendously costly, and makes up round 77 per cent of the price of a gasoline cell, as estimated by the Nationwide Renewable Vitality Laboratory within the US.
Yuan Chen from the College of Sydney is an knowledgeable in utilizing carbon supplies to cut back the price of hydrogen gasoline cells.
“We’re changing the platinum with single-atom catalysts, the place the atom is iron, nickel and cobalt, embedded into carbon,” he defined.
Additional work is underway to enhance the soundness of those platinum replacements, however they’ve up to now reached the milestone of acting at an analogous effectivity because the costlier platinum catalyst.
Carbon can enhance photo voltaic effectivity too
Timothy Schmidt is main a crew on the College of New South Wales to enhance the effectivity of photo voltaic cells utilizing carbon-based coatings.
“One of the best silicon photo voltaic cells max out at 26 per cent effectivity and engineers can scramble to make them extra environment friendly, however they’re operating up towards a ceiling,” he mentioned.
The explanation silicon photo voltaic cells usually are not extra environment friendly is that they’ll solely rework particular colours of sunshine into electrical energy. Redder gentle is transformed most effectively, however as the sunshine will get bluer, it produces extra warmth.
Professor Schmidt’s crew is engaged on a coating to place atop a silicon photo voltaic cell to transform blue gentle into redder gentle that silicon can effectively take up. This has the sci-fi identify of a “singlet-fission photo voltaic cell”.
If the carbon-based coating can improve the quantity of power produced by the photo voltaic cell, it might enhance panel effectivity by as much as 35 per cent within the subsequent 5 to 10 years.
Whereas a hike from 26 to 35 per cent does not sound like lots, it makes an enormous distinction in the case of photo voltaic payback time.
For instance, growing the effectivity of a photo voltaic cell from 12 per cent to 14 per cent halved the payback time for a photo voltaic system from 4 to 2 years, in accordance with researchers from Utrecht College within the Netherlands (though photo voltaic effectivity is not the one issue that impacts payback time).
These are only a handful of many initiatives in Australia and overseas utilizing carbon supplies to construct and refine inexperienced power expertise.
And regardless of its dangerous repute, carbon can assist us attain our local weather objectives.
Dr Jacob Martin is a supplies and combustion scientist at Curtin College.
He’s additionally one of many ABC’s Prime 5 scientists for 2022.