A material has been identified by US researchers studying ions at the microscopic level, which may lead to the next generation of batteries and supercapacitors.
By identifying the properties of the material MXene, and what drives its energy storage properties, scientists at the Department of Energy’s Oak Ridge National Laboratory hope to have discovered a way to develop the next generation of batteries.
ORNL’s Fluid Interface Reactions, Structures and Transport (FIRST) research team observed at the nanoscale, and in a liquid environment, how ions move and diffuse between layers of a two-dimensional electrode during electrochemical cycling.
The researchers observed how ions enter and move once inside the materials and how they interact with the active material by combining advanced in-situ microscopy and theoretical calculations.
Nina Balke, was one of a team of researchers working with Drexel University’s Yury Gogotsi in the FIRST Center, a DOE Office of Science Energy Frontier Research Center.
Balke said: “We have developed a technique for liquid environments that allows us to track how ions enter the interlayer spaces. There is very little information on how this actually happens.
“The energy storage properties have been characterised on a microscopic scale, but no one knows what happens in the active material on the nanoscale in terms of ion insertion and how this affects stresses and strains in the material.”
Based on MAX-phase ceramics, the MXene material could be fabricated with the flexibility of a sheet of paper, say the researchers.
A statement on ORNL’s website explained the process as a “Chemical removal of the “A” layer leaves two-dimensional flakes composed of transition metal layers (the M) sandwiching carbon or nitrogen layers (the X) in the resulting MXene, which physically resembles graphite.
“The interaction and charge transfer of the ion and the MXene layers is very important for its performance as an energy storage medium,” said FIRST researcher Jeremy Come.
The researchers’ next steps are to improve the ionic diffusion paths in the material and explore different materials from the MXene family.
The findings work were published in the Journal Advanced Energy Materials.
