Lithium-carbon dioxide batteries are thought to be better energy storage systems because they have a specific energy density that is greater than commonly used lithium-ion batteries. Until now, scientists could not develop a fully rechargeable prototype, despite their potential to store more energy.
A team at the University of Illinois at Chicago (UIC) claims to have developed the first lithium-carbon dioxide battery capable of full rechargeability. The technical problem the researchers have overcome centres on the tendency of these batteries to quickly fail due to the buildup of carbon on the catalyst during charging, which has plagued similar efforts so far.
"The accumulation of carbon not only blocks the active sites of the catalyst and prevents carbon dioxide diffusion, but also triggers electrolyte decomposition in a charged state," said Alireza Ahmadiparidari, first author of the paper and a UIC College of engineering graduate student.
A way around this, the researchers have found, is to introduce new materials that shore up the battery's ability to recycle the materials, over and over. This meant integrating nanoflakes of molybdenum disulphide into the cathode catalyst, and using a new type of hybrid electrolyte made of ionic liquid and dimethyl sulfoxide.
This combination, the researchers say, leads the battery to output a composite made up of multiple components rather than individual products, which sees the carbon naturally incorporated into the recycling process rather than form a troublesome buildup on the battery's catalyst on its own. So much so, they were able to recharge their prototype battery across 500 consecutive cycles.
"Our unique combination of materials helps make the first carbon-neutral lithium carbon dioxide battery with much more efficiency and long-lasting cycle life, which will enable it to be used in advanced energy storage systems," says associate professor of mechanical and industrial engineering, Salehi-Khojin.
This research is a long way from commercial production, and even further away from putting a dent in the carbon dioxide that is continuing to build up in the atmosphere. It does, however, provide yet another proof-of-concept energy storage device for a next-generation battery, along with yet another possible way we might one day be able to channel carbon dioxide into something more useful.