The device currently measures 1-inch by 1-inch, but the team from the University of Houston, Texas, Jackson State University, Mississippi, and Howard University, Washington, DC said it could be scaled up to ‘potentially revolutionise energy storage systems’.
The team’s findings are detailed in ACS Nano.
In a statement, Alamgir Karim, Dow Chair and Welch Foundation Professor of Chemical Engineering at UH, said: “High-energy and high-power capacitors are essential for a reliable power supply, especially as we shift to using more renewable energy sources. However, current dielectric capacitors don't store as much energy as other types of energy storage devices such as batteries. The higher power density of capacitors makes them more attractive for a multitude of applications as compared to batteries.”
The amount of energy a capacitor can store depends on its permittivity and dielectric breakdown strength.
“To increase a capacitor's energy storage, we need to improve both,” said Karim.
In this study, the researchers designed a new type of capacitor using layered polymers with oriented 2D nanofillers derived from mechanically exfoliated flakes of 2D materials.
The researchers maximised energy storage by arranging these materials in specific layers, creating a structure to improve capacitor performance. According to UH, this new design showed improved performance with higher energy density and efficiency than capacitors with randomly blended-in nanofillers.
"Our work demonstrates the development of high energy and high-power density capacitors by blocking electrical breakdown pathways in polymeric materials using the oriented 2D nanofillers," said Maninderjeet Singh, first author on the paper along with Priyanka Das from Jackson State University. "We achieved an ultra-high energy density of approximately 75J/cm³, the highest reported for a polymeric dielectric capacitor to date."
The research team utilised materials like mica and hexagonal boron nitride (hBN) to demonstrate the effectiveness of controlling 2D nanosheet orientation in blocking electrical breakdown pathways. UH added that significant enhancements in dielectric permittivity were observed, even with a minimal volume fraction (one per cent) of nanofillers.
“With the help of mechanical exfoliation and transfer techniques, we successfully achieved the desired orientation," said Karim.
Now that the researchers have demonstrated the first-of-its-kind use of stratified multilayered nanocomposites for the design of polymeric energy storage devices, the team expects these hybrid capacitors to be used in a range of applications and will work on extending energy storage capabilities by developing continuous organic-inorganic interfaces.
The researchers envision the capacitors eventually being used in medical devices like pacemakers and defibrillators, as well as applications in electronics, electric vehicles, power systems, and more.
"This research provides valuable insights into dielectric breakdown and charge polarisation phenomena in 2D polymer nanocomposites," said Singh, who is now a postdoctoral research scientist at Columbia University. "We believe that our findings will inspire further studies to develop even higher energy-density capacitors, contributing to a cleaner and more sustainable future."
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