New Lithium-Based Battery Design Makes Use of Greenhouse Gas Before it Ever Get into the Atmosphere

1,224

A new type of battery developed by researchers at MIT could be made partly from carbon dioxide captured from power plants. Rather than attempting to convert carbon dioxide into specialized chemicals using metal catalysts, which is currently highly challenging, this battery could continuously convert carbon dioxide into a solid mineral carbonate as it discharges. The battery is made from lithium metal, carbon, and an electrolyte that the researchers designed.

The new battery formulation could open up new avenues for tailoring electrochemical carbon dioxide conversion reactions, which may ultimately help reduce the emission of the greenhouse gas to the atmosphere. The findings are described in the journal Joule, in a paper by assistant professor of mechanical engineering Betar Gallant, doctoral student Aliza Khurram, and postdoc Mingfu He.

Currently, power plants equipped with carbon capture systems generally use up to 30% of the electricity they generate just to power the capture, release, and storage of carbon dioxide. Anything that can reduce the cost of that capture process, or that can result in an end product that has value, could significantly change the economics of such systems, the researchers say.

However, “carbon dioxide is not very reactive,” Gallant explains, so “trying to find new reaction pathways is important.” Generally, the only way to get carbon dioxide to exhibit significant activity under electrochemical conditions is with large energy inputs in the form of high voltages, which can be an expensive and inefficient process. Ideally, the gas would undergo reactions that produce something worthwhile, such as a useful chemical or a fuel.

Gallant and her co-workers, whose expertise has to do with nonaqueous (not water-based) electrochemical reactions such as those that underlie lithium-based batteries, looked into whether carbon-dioxide-capture chemistry could be put to use to make carbon-dioxide-loaded electrolytes, one of the three essential parts of a battery, where the captured gas could then be used during the discharge of the battery to provide a power output.

They showed through a series of experiments that this approach does work, and can produce a lithium-carbon dioxide battery with voltage and capacity that are competitive with that of state-of-the-art lithium-gas batteries. Carbon capture is widely considered essential to meeting worldwide goals for reducing greenhouse gas emissions, but there are not yet proven, long-term ways of disposing of or using all the resulting carbon dioxide.

Ultimately, they hope to make this into an integrated system that will carry out both the capture of carbon dioxide from a power plant’s emissions stream, and its conversion into a material that could then be used in batteries.