A recent breakthrough suggests "holey" graphene could boost electrical charge and provide a better understanding of how to improve the storage abilities of capacitors, which could be used in cars, winds turbines, and solar power technology.
Capacitors charge and discharge at breakneck speeds, and are most efficient for large bursts of energy, such as camera flashes, the University of California, San Diego reported. The downside is this causes them to have a reduced capacity for energy storage. To combat this, scientists introduced more charge into a capacitor electrode using graphene.
Creating a carbon nanotube structure without imperfections is almost impossible, so researchers decided to take advantage of these flaws.
"I was motivated from the point of view that charged defects may be useful for energy storage," said mechanical engineering professor Prabhakar Bandaru at the Jacobs School of Engineering at UC San Diego.
The team employed a method called "argon-ion based plasma processing," in which graphene samples are hit with positively charged ions. The carbon atoms knock out some of the graphene's layers, leaving behind microscopic holes that contain positive charges. Once exposed to argon plasma, the capacitance of the material proved to be boosted three-fold.
"It was exciting to show that we can introduce extra capacitance by introducing charged defects, and that we could control what kind of charged defect we could introduce into a material," said Rajaram Narayanan, a graduate student in professor Bandaru's research group and first author of the study.
Spectroscopy and electrochemical measurements allowed the team to characterize the types of defect imposed onto a graphene lattice into "armchair" and "zigzag" categories. The careful study also produced a new length scale that can measure the distance between charges.
"This new length scale will be important for electrical applications, since it can provide a basis for how small we can make electrical devices," Bandaru concluded.
The findings were published in a recent edition of the journal Nano Letters.
