Here’s what you’ll learn when you read this story:

• Though supercapacitors are a new frontier for outperforming batteries and other power and energy sources, the materials they were previously made of were problematic.
• Graphene used in supercapacitors has a rigid crystal structure that makes it difficult for ions to move around and does not allow them to be stored in the spaces between graphene sheets.
• By creating a new graphene material, engineers were able to facilitate the movement of ions and increase the power and energy capacity of their supercapacitors.

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Supercapacitors are the answer to power and energy burnout. With more power density (or power per unit of space) than batteries and more energy density than dielectric capacitors (which store electric charge), these hybrids of the future should be able to merge superfast charging with a power boost. But they currently have one major drawback: The materials they are made of are not able to take advantage of their entire storage capacity.

Graphene is one of the materials often used to make the electrodes in these atomic fuel tanks, as its carbon’s superior conductivity allows ions to travel faster and provides more surface area on which to store them. The issue is that only a fraction of that surface area is actually available, and previous efforts to optimize surface area have still not been enough.

Enter mechanical engineer Mainak Majumder and his research team at Monash University in Australia. Aware that demand for high volumes energy density is increasing right alongside demand for compact and portable electronics, Majumder set out to devise a solution for supercapacitor setbacks. The reason that current technology falls short is because of chemical interactions that make it impossible for ions to adhere to spaces between sheets of graphene in 3D structures. While the design flexibility of graphene makes it possible to create denser electrodes, which in turn make it easier for ions to move around, they are still not using much of the potential storage capacity they have.

“We design[ed] a graphene structure tailored to deliver volumetrically-efficient capacitive energy storage,” Majumder said in a study recently published in Nature Communications. “By integrating nano- and meso-scale features of graphene in micron-sized particles, we demonstrate that a multiscale structure, benefiting from each scale, enhances ion accessibility, transport kinetics, energy storage capacity and long-term stability.”

The team realized they needed to change how they treated graphene with heat. Australia has vast reserves of graphite, from which graphene is created. The team heated graphite oxide powder rapidly and cooled the resulting substance—an emerging material known as multiscale reduced graphene oxide (M-rGO)—slowly so that it could be more workable and prevent internal stress that could cause it to break.

Unlike graphite, graphene has the advantage of chemical interactions between its sheets, whose carbon atoms are arranged in honeycomb structures. (These sheets are as thick as one atom, making them two-dimensional.) These interactions create what Majumder calls “reactive energetic hotspots” that facilitate movement for ions. Normally, pathways for ions in stacked graphene sheets limit capacity because they are difficult for the ions to maneuver through. But after heating and cooling, the transformed M-rGO structure’s curved nanocrystals and disordered graphene sheets served as both highways and reservoirs for ions that significantly increased storage capacity.

The new electrodes were incorporated into pouch cell devices. These flexible, lightweight cells—which are far more efficient than most batteries—allow for a higher energy density, making them ideal for use in electronics. They can be found in not just in electric vehicle batteries, but in gadgets like drones, tablets, and smartphones. Majmuder’s supercapacitors not only outperformed previous graphene structures with especially high energy and power densities, but remained stable, and charged in almost no time. They were so successful that commercialization is already on the horizon.

“Thanks to an extended voltage window […] these pouches deliver a [high] volumetric energy density,” he said. “High volumetric energy and power densities in both organic and ionic liquid electrolytes highlights the powerful role of multiscaling to manipulate active sites, energy storage mechanisms and ion transport.”

Elizabeth Rayne is a creature who writes. Her work has appeared in Popular Mechanics, Ars Technica, SYFY WIRE, Space.com, Live Science, Den of Geek, Forbidden Futures and Collective Tales. She lurks right outside New York City with her parrot, Lestat. When not writing, she can be found drawing, playing the piano or shapeshifting.