Researchers from the University of Illinois at Chicago College of Engineering are reporting that graphene (bonded carbon atoms in a sheet form one-atom thick) may take the oxygen out of lithium battery fires.
The report explains that the reasons lithium batteries catch fire include rapid cycling or charging and discharging, and high temperatures in the battery. These conditions can cause the cathode inside the battery — which in the case of most lithium batteries is a lithium-containing oxide, usually lithium cobalt oxide — to decompose and release oxygen. If the oxygen combines with other flammable products given off through decomposition of the electrolyte under high enough heat, spontaneous combustion can occur.
When researchers looked at the graphene-wrapped lithium cobalt oxide particles using electron microscopy, they saw that the release of oxygen under high heat was reduced significantly compared with unwrapped particles.
Next, they bound together the wrapped particles with a binding material to form a usable cathode, and incorporated it into a lithium metal battery. When they measured released oxygen during battery cycling, they saw almost no oxygen escaping from cathodes even at very high voltages. The lithium metal battery continued to perform well even after 200 cycles.
Reza Shahbazian-Yassar, associate professor of mechanical and industrial engineering in the UIC College of Engineering and corresponding author of the paper explains, “Graphene is the ideal material for blocking the release of oxygen into the electrolyte. It is impermeable to oxygen, electrically conductive, flexible, and is strong enough to withstand conditions within the battery. It is only a few nanometers thick so there would be no extra mass added to the battery. 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.”
Unfortunately, the promising research didn’t come soon enough for Ocean Beach’s Ace Elliot who lost his surfboard business to a fire he believes started from charging his e-bike. Until companies adopt the graphene treatment (or something similar), please take our advice for the charging and storage of your e-bike. It just might save you the heartache Ace Elliot has to suffer.