An Energy Storage Technology That Could Reduce Charging Time to Minutes

Researchers from Tulane University developed an energy storage technology that could reduce charging time to a matter of minutes compared to lithium-ion batteries.  The study was funded by the Department of Energy’s Energy Frontier Research Center as part of the Fluid Interface Reactions, Structures, and Transport (FIRST) Center.

The research – engineering the interlayer spacing by pre‐intercalation for high-performance supercapacitor MXene electrodes in room temperature ionic liquid – has been published in the journal Advanced Functional Materials.

Led by Tulane University assistant professor Michael Naguib, the research revolves around MXenes, promising energy storage materials that are conductive and can host ions, such as lithium, between layers.

MXenes are a class of two-dimensional inorganic compounds that combine the metallic conductivity of transition metal carbides with a hydrophilic nature because of their hydroxyl- or oxygen-terminated surfaces. The new materials, using ionic liquids, can combine the energy density of lithium-ion batteries with the rapid power charging of supercapacitors.

The team worked on MXenes at the nanoscale to develop new techniques to optimize the space between those layers, allowing larger ions to enter. According to the researchers, this can help bridge the gap between the rapid charging advantages of supercapacitors, or aqueous electrochemical capacitors, with the density of lithium-ion batteries.

Room-temperature ionic liquids are promising electrolytes because they provide stability and a larger energy density. But because their ions are so large, they’re unable to get between the MXene layers, and in turn, the amount of energy stored is limited.

While lithium-ion batteries offer one of the highest energy densities, according to Naguib, “They still struggle when it comes to high charging rates, and their electrolytes exhibit some safety concerns. On the other hand, aqueous electrochemical capacitors, also known as supercapacitors, can deliver a very high power, but their energy density is limited.”

“Here, we introduced wedges or pillars between the layers to open them up, allowing the ionic liquid ions to get stored between the MXene layers, thus achieving very high energy and power densities,” Naguib said.

In addition to authors from Tulane, the team for this study consisted of researchers from Oak Ridge National Laboratory, Vanderbilt University, North Carolina State University, and the National Institute of Standards and Technology.

In December last year, QuantumScape, one of the leading developers of solid-state lithium metal batteries for use in EVs, had claimed to have developed a new solid-state lithium battery that can increase the range of electric vehicles by 80%.

Earlier, researchers at Penn State University claimed to have developed a lithium-ion battery that is safe and has power, and can last up to one million miles.