Taking Charge

  Pseudocapacitors are effective at storing energy in part because of the vacant spots where oxygen ions can be stored.

Pseudocapacitors are effective at storing energy in part because of the vacant spots where oxygen ions can be stored.

All-electric vehicles, like the Nissan Leaf, have been slow to catch on in the U.S., in part because they have a short driving range, require large, expensive batteries and take several hours to charge. To solve these problems, scientists and engineers have been experimenting with energy storage devices called pseudocapacitors that can charge and discharge much faster than commercial batteries. Combined with batteries, they offer the best of both worlds: long-term energy storage and rapid charging.

Unlike other devices, the team’s is the first to use oxygen anions (negatively-charged ions) instead of cations (positive ions) to store its energy.

Now a team of scientists led by Keith Stevenson, Louis Nicolas Vauquelin Regents Professor in Inorganic Chemistry, has developed the first of a new class of pseudocapacitor that could eventually lead to better electric vehicles. Unlike other devices, the team’s is the first to use oxygen anions (negatively-charged ions) instead of cations (positive ions) to store its energy.

“One main advantage of oxygen ions is that they allow you to theoretically store double the energy, providing two electrons per ion stored,” said Tyler Mefford, graduate student and lead author of the study in Nature Materials.

Another benefit is that, unlike cation-based pseudocapacitors, which use rare and expensive metals, this anion-based device uses cheap metals that are abundant in Earth’s crust.

Improved pseudocapacitors may also find applications in fast-charging cell phones or in electric power grids to stabilize electricity flow from fickle solar panels and wind turbines.

Go online for more information on this and the year in discoveries: links.utexas.edu/ubbqqj

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