Could explosive lithium-ion batteries and all the injury and property damage they cause soon be a thing of the past?
Researchers with the University of Maryland and the U.S. Army Research Laboratory have developed the world’s first lithium-ion battery that uses a salt-water electrolyte and hits the 4.0-volt mark needed for laptop computers and other household electronics without the risk of explosion and fire that traditional non-aqueous lithium-ions present.
“In the past, if you wanted high energy, you would choose a non-aqueous lithium-ion battery, but you would have to compromise on safety. If you preferred safety, you could use an aqueous battery such as nickel/metal hydride, but you would have to settle for lower energy,” says co-senior author Kang Xu, a lab fellow at the U.S. Army Research Laboratory specializing in electrochemistry and materials science. “Now, we are showing that you can simultaneously have access to both high energy and high safety.”
The latest paper follows on news from a 2015 publication in Science journal, in which the same team announced its development of a similar aqueous electrolyte battery that reached the 3.0-volt mark.
The problem presented by the earlier battery was that it prevented the researchers from reaching higher voltages by a process known as “cathodic challenge,” where the lithium anode end of the battery is degraded by the water-based electrolyte.
To solve that problem, the aqueous lithium battery uses a gel polymer that decomposes on the battery’s first charge to create a stable protective layer called an “interphase,” which protects the anode from degradation. Once the anode is coated in this protective layer, the battery’s charge is able to reach 4.0 volts.
“The key innovation here is making the right gel that can block water contact with the anode so that the water doesn’t decompose and can also form the right interphase to support high battery performance,” said co-senior author Chunsheng Wang, Professor of Chemical & Biomolecular Engineering at the University of Maryland’s A. James Clark School of Engineering.
Dr. Xu said the interphase chemistry will have to be perfected before the batteries can be commercialized, but he estimates the batteries will be on the market in about five years.