Dip in Carbon Nanotubes Improve Batteries, Ultracapacitors
“A simple trick could improve the ability of advanced ultracapacitors, or supercapacitors, to store charge.
The technique, developed by Stanford University researchers, could enable the use of new types of nanostructured electrode materials that store more energy.
While ultracapacitors provide quick bursts of power and can be recharged many more times than batteries without losing their storage capacity, they can store only a 10th as much energy as batteries, which limits their applications.
To improve their energy density, researchers have focused on the use of electrode materials with greater surface area—such as graphene and carbon nanotubes—which can hold more charge-carrying ions.
The Stanford team, led by Yi Cui and Zhenan Bao, used composite electrodes made of graphene and manganese oxide.
Manganese oxide is considered an attractive electrode material because, “one, manganese is abundant so it’s very low cost,” Cui says. “It also has high theoretical capacity to store ions for supercapacitors.””