Whilst lithium batteries are driving progress in everything from electric vehicles, to mobile phones, grid-storage and umpteen other technologies, but they have a major shortfall. They’ve been known to spontaneously combust under not-so-extraordinary conditions (just ask Dutch firemen) and when they burn, they burn or a while.
However, researchers from the University of Illinois at Chicago College of Engineering may have found the solution - graphene – which they claim can take the oxygen out of lithium batteries, and extinguish the fire.
According to the University, a lithium battery fire is subject to “thermal runaway” where cathode of the battery decomposes due to rapid cycling over over-heating. The cathode then releases oxygen, which can result in combustion. They’ve found that graphene sheets, made up of a microscopically-thin layer of carbon atoms block oxygen, and are strong enough to be made electrically conductive.
The lithium cobalt oxide particles that make up the cathode are wrapped in conductive graphene, and are then subjected to heat. What researchers observed is that the oxygen release was significantly lower than unwrapped particles.
The team has also developed a viable cathode out of conductive graphene, which they say results in almost no oxygen release, even at very high voltages.
Reza Shahbazian-Yassar, Associate Professor of Mechanical and Industrial Engineering said: “Graphene is the ideal material for blocking the release of oxygen into the electrolyte.
“Our research shows that its use in the cathode can reliably reduce the release of oxygen and could be one way that the risk for fire in these batteries — which power everything from our phones to our cars — could be significantly reduced.”