Researchers have developed a new material which may one day replace conventional plastic or polymer separators in lithium-ion batteries.
Materials scientists at Rice University, US, made an electrolyte using nonflammable, hexagonal boron nitride (h-BN), sometimes referred to as “white graphene”.
The atom-thin compound combines the electrolyte and seperator to allow rechargeable lithium-ion batteries to supply usable voltages at high temperatures
Though inert, the mix of h-BN, piperidinium-based ionic liquid and a lithium salt catalysed a better reaction from all the chemicals around it, stated results published in the journal Advanced Energy Materials.
The Rice team, led by Pulickel Ajayan, said batteries made with the composite could operate up to 150 degrees Celsius for more than a month with little energy density loss.
Although h-BN is not a conductor, or known to be an ionic conductor, lead author of the paper Marco-Túlio Rodrigues, a Rice graduate student, said they used it because they wanted a material that was chemically and mechanically resistant, even at very high temperatures, but which would give stability to the electrolyte layer.
He said: “We tested our composite against benchmark electrodes and found that the batteries were stable for more than 600 cycles of charge and discharge at high temperatures.”
Batteries using the electrolyte would suit industrial and aerospace applications that operate in high temperatures where conventional plastic or polymer separators tend to shrink or melt, said Rice postdoctoral researcher and co-author Hemtej Gullapalli.
“It took almost two years to confirm that even though the boron nitride, which is a very simple formulation, is not expected to have any chemical reaction, it’s giving a positive contribution to the way the battery works,” Gullapalli said. “It actually makes the electrolyte more stable in situations when you have high temperature and high voltages combined.”
Co-authors are Rice graduate student Kaushik Kalaga and Wayne State postdoctoral fellow Ganguli Babu. Ajayan is chair of Rice’s Department of Materials Science and NanoEngineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry.
Picture: Postdoctoral research Hemtej Gullapalli, left), and graduate student Marco-Túlio Rodrigues from Rice University. Photo by Jeff Fitlow
