Team improves supercapacitor performance for better energy storage

Posted by Kate Taylor

Researchers at The University of Texas at Austin have created a greatly enhanced supercapacitor, improving energy storage in everything from energy grids and electric cars to consumer electronics.

Supercapacitors can deliver energy much faster and more efficiently than batteries - but usually hold much less electrical charge. But, says the team, their new porous, three-dimensional carbon changes all that.

"We synthesized a new sponge-like carbon that has a surface area of up to 3,100 square meters per gram - two grams has a surface area roughly equivalent to that of a football field," says materials science and mechanical engineering Professor Rodney S. Ruoff.

"It also has much higher electrical conductivity and, when further optimized, will be superb for thermal management as well."

The team synthesized the carbon material by using microwaves to exfoliate graphite oxide. This was followed by treatment with potassium hydroxide, which created a carbon full of tiny holes — essentially a sponge that, when combined with an electrolyte, can store a giant electrical charge.

They then analyzed the atomic structure of the carbon material at the nanoscale using very high resolution electron microscopes, and confirmed that the carbon was a new three-dimensional material with highly curved, single-atom-thick walls that form tiny pores.

"After we realized that we had a new carbon with a highly novel structure that showed superb performance as an electrode, we knew that this direction of research — to create carbon materials that consist of a continuous three-dimensional porous network with single-atom-thick walls — was likely to yield the optimum electrode material for supercapacitors," says Ruoff.

The processes used to make this porous carbon are readily scalable to industrial levels, says Ruoff, and the university's Office of Technology Commercialization has filed for a patent.