Nitrogen and Argon Plasma Improves Performance of Carbon-Based Supercapacitor Electrodes

Image. A colored micrograph showing unmodified carbon nanowalls as seen with a scanning electron microscope. Credit: Stanislav Elvashin.

Scientists from Skoltech, the Institute of Nanotechnology of Microelectronics at the Russian Academy of Sciences and collaborating research institutions have made progress in understanding how plasma treatment influences the key properties of carbon-based electrodes in supercapacitors.

These devices, which are used alongside batteries in electric vehicles, trains, port cranes, and more, are being closely studied to improve their energy storage capabilities. By exploring how different electrode modifications impact capacitance, researchers aim to expand the range of techniques available to boost supercapacitor performance. The results of this study were published in Electrochimica Acta and funded by the Russian Science Foundation.

“Our research focuses on enhancing supercapacitor efficiency by modifying the carbon materials used in their electrodes,” explained Assistant Professor Stanislav Evlashin of Skoltech Materials, the study’s lead researcher. “There are primarily two approaches to increasing a supercapacitor’s energy storage: increasing the surface area of the electrodes through structural design,or introducing foreign atoms into the carbon material. In this work, we advanced our understanding of how the introduction of foreign atoms affects performance.”

Image. A colored micrograph showing unmodified carbon nanowalls as seen with a scanning electron microscope. Credit: Stanislav Elvashin

Supercapacitors are often paired with lithium-ion batteries because they can rapidly store and release energy, making them ideal for applications requiring quick power surges, such as lifting heavy loads or accelerating vehicles. They function well across a broad range of temperatures, experience minimal wear, have long operational lifespans, and can significantly extend the life of lithium-ion batteries. Unlike some traditional battery technologies, supercapacitors pose minimal fire risk and are composed of materials that are relatively easy to dispose of in an eco-friendly manner.

Supercapacitors provide reliable backup power for critical systems in hospitals, data centers, and telecommunications, ensuring uninterrupted operation and preventing data loss. They are also employed to balance peak loads on the electrical grid. Additionally, this technology shows promise for powering Internet of Things (IoT) sensors, communication devices, wearable medical gadgets, and portable electronics.

In electric and hybrid vehicles, supercapacitors support functions like startup, braking, and power steering. When paired with internal combustion engines, they contribute to faster battery charging. More broadly, electric vehicles—and especially trains—can harness the energy recovered during braking through supercapacitors, enhancing overall energy efficiency.

The higher a supercapacitor’s capacitance, the more energy it can hold. Researchers at Skoltech are examining how introducing foreign atoms into the carbon material used in supercapacitor electrodes influences this capacitance.

In their recent study published in Electrochimica Acta, the team evaluated the impact of plasma treatments using six different chemical compositions on carbon nanowalls—a common electrode material in supercapacitors. Among these, only the nitrogen-argon mixture significantly enhanced performance, doubling the material’s areal capacitance. Although not a record-breaking result, the study offers valuable insights into the underlying electrochemical processes.

“We discovered that the process begins with the removal of amorphous carbon left behind after the carbon nanowall structures are formed,” explained Evlashin. “This is followed by the creation of new defects and the integration of heteroatoms into the carbon framework. Both the residual amorphous carbon and the introduced nitrogen atoms contribute to the development of pseudocapacitance.”