Energy

MIT's lithium-carbon dioxide battery generates power and solidifies carbon

MIT's lithium-carbon dioxide b...
A scanning electron microscope image of the carbon cathode of MIT's new lithium-carbon dioxide battery. Over time carbon dioxide builds up in a solid form on the surface, as compared to the original surface state (inset)
A scanning electron microscope image of the carbon cathode of MIT's new lithium-carbon dioxide battery. Over time carbon dioxide builds up in a solid form on the surface, as compared to the original surface state (inset)
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A scanning electron microscope image of the carbon cathode of MIT's new lithium-carbon dioxide battery. Over time carbon dioxide builds up in a solid form on the surface, as compared to the original surface state (inset)
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A scanning electron microscope image of the carbon cathode of MIT's new lithium-carbon dioxide battery. Over time carbon dioxide builds up in a solid form on the surface, as compared to the original surface state (inset)

As the world warms up, it's becoming increasingly obvious that we can't just keep belching all our carbon dioxide out into the atmosphere. Scientists are searching for ways to pluck it out of the air and stash it underground, store it in concrete, turn it into carbon nanofibers or even make fuel out of it. Now researchers at MIT have found another way to reuse this unwanted element – build lithium-carbon dioxide batteries.

Carbon dioxide may sound versatile given that list of possible uses, but the problem is that converting it into different forms often requires high voltages and plenty of energy. That can cancel out the benefits of removing it from the atmosphere in the first place.

So the MIT team set out to see if CO2 could be captured and used in a battery. Because CO2 isn't very reactive, previous attempts at lithium-carbon dioxide batteries have needed to use metal catalysts, but the researchers here found a way to do so using a carbon electrode instead.

First, the carbon dioxide is preactivated by incorporating it into an amine solution. This watery solution is then combined with another liquid electrolyte, and used in the battery with a carbon cathode and a lithium anode.

"What we've shown for the first time is that this technique activates the carbon dioxide for more facile electrochemistry," says Betar Gallant, an author of the study. "These two chemistries — aqueous amines and nonaqueous battery electrolytes — are not normally used together, but we found that their combination imparts new and interesting behaviors that can increase the discharge voltage and allow for sustained conversion of carbon dioxide."

Not only does the battery provide power on a level comparable to existing lithium-gas batteries, but as it discharges it converts the carbon dioxide in the electrolyte into a solid mineral carbonate form. That's a much more efficient way to convert CO2 from a gas to a solid than most other techniques, and that solid form can then be used for other purposes – including making the carbon cathode for future batteries.

The current version is a proof-of-concept however, and the researchers say that commercial lithium-carbon dioxide batteries are still years away. In the meantime, several other problems need to be sorted out, such as rechargeability – for now, the battery can only run for about 10 cycles.

In future, the team says the system could also be adapted into a continuous-operation version. That means that rather than using up the preloaded supply of CO2, a steady stream of the stuff could be funneled through the system, converting the gas into a usable solid form and generating power in the process.

The research was published in the journal Joule.

Source: MIT

11 comments
watersworm
CO2 an "unwanted element" ??? Ask plants and the Planet in general when more CO2 in the atmosphere leads to a greater greening of the Planet.
minivini
That’s a delusional comment. Plants have evolved, just like mammals, to use CO2 in the ratio it exists in nature - a little less than 1%. Just like if O2 levels increased much beyond the current 21%, it would be bad news for us animals, the worlds plant population would suffer from too much CO2. I’m going to surmise by your comment that you don’t believe CO2 is the primary culprit in climate change, but yes - that, too, is a nasty byproduct of too much CO2.
warmisgood
Below is an excerpt from a university study on ideal CO2 levels in Greenhouses for plant growth.. Current CO2 PPM levels in the world are around ~400 ppm. "Supplementation of CO2 is seen as beneficial for most crops. The level to which the CO2 concentration should be raised depends on the crop, light intensity, temperature, ventilation, stage of the crop growth and the economics of the crop. For most crops the saturation point will be reached at about 1,000–1,300 ppm under ideal circumstances."
Douglas Bennett Rogers
Cellular metabolism requires about 4% CO2. This was the concentration of CO2 when cellular life evolved. Dessert irrigation represents about five times the greenhouse effect of industrial CO2.
Lamar Havard
Converting CO2 doesn’t require anything but plants. And the more there is, the more oxygen plants produce for US to use. So, use some CO2 to make your batteries and charge us more to buy them even though they cost YOU less to build.
ChairmanLMAO
pretty much CO that we don't want but what would we drive? who would pay for the gas we need to keep the economy running?
Ryan Cragg
The "CO2 is plant food" argument is a little too simplified. In the real world, outside of the greenhouse, increased CO2 has little benefit to most plants. https://skepticalscience.com/co2-is-plant-food-too-simple.html minivini is more correct than watersworm or warmisgood
Kpar
minivini, learn some geology. CO2 has been present in much larger quantities in the past (during both warm periods and cold) and modern commericial greenhouses use concentrations much more than TEN TIMES greater than in the atmosphere. Besides, CO2 is a compound, not an element...
MarkGatti
good grief ,there are still people who believe in anthropomorphic global warming !? it was dreamed up purely as a political tool to redistribute wealth [incredibly inefficiently as it turns out ],, 3 ipcc members are now on record admitting this !!. [ fyi the ratio of o2 and nitrogen is locked ,worldwide ,to a very fine tolerance ,has baffled science ,except prof pollack may have found a reason at last ]. unlike the fact that co2 is greenhouse gas !! ,meaning they pump more ,much more ,into greenhouses to benefit the plants . The big hot ball in the sky however is at a Maunder minimum [look it up ] which is quite unnerving ,as this is linked to both cooling and increased volcanic activity , factorsinc that could lead to more water in atmosphere and it getting frozen ,,as ,,mini ice age ! ,, this could affect the polar bears ,that are flourishing at present thanks .
BeinThayer
Ryan Cragg, the 'skeptical science' page you linked to is written by someone either with poor reading comprehension that happened to make papers align with their worldview or with the intent to distort acedemic papers to support the their worldview. The page stated outdoor open air enhanced CO2 studies yielded 50% less than greenhouse enhanced CO2 studies. The linked papers don't say that. They say that the outdoor studies showed up to a 50% reduction in the in the yield Enhancement for outdoor vs greenhouse. Note, the yield isn't half, the improvement in yield is could be just half of indoor experiments. Even at half, the improvement can be sizeable. The importance of reading with a critical eye is not diminished just because what you are reading supports your argument. If anything it becomes even more important.