UT and ORNL researchers develop new class of pseudocapacitor; anion-based intercalation pseudocapacitance
31 July 2014
Scientists in the The University of Texas at Austin’s College of Natural Sciences and the Cockrell School of Engineering, in collaboration with a researcher at the Department of Energy’s Oak Ridge National Laboratory, have developed the first of a new class of pseudocapacitor that may eventually lead to devices that can store electricity more densely and charge/discharge more quickly than other types of pseudocapacitors built to date.
In the journal Nature Materials, the team led by professor Keith Stevenson reports a new energy storage mechanism for pseudocapacitor electrodes that promises to boost the energy density and power density of pseudocapacitor devices. Unlike other devices, the team’s is the first to utilize oxygen anions (negatively-charged ions) instead of cations (positive ions) to store its energy.
This is the first example of anion-based intercalation pseudocapacitance as well as the first time oxygen intercalation has been exploited for fast energy storage. Whereas previous pseudocapacitor and rechargeable battery charge storage studies have focused on cation intercalation, the anion-based mechanism presented here offers a new paradigm for electrochemical energy storage.
—Mefford et al.
The device uses a perovskite material (LaMnO3), a structure containing vacant sites where oxygen anions can be stored, making these advancements a possibility.
One main advantage of oxygen ions is that they can allow you to theoretically store double the energy, providing two electrons per ion stored. It’s also a proof of concept that this kind of charge storage strategy can work, so we can continue research in this area to make them better and better.
It’s already competitive with a lot of the cation ones but there may be even better anion-based materials out there. Another benefit is that the really high performing cation-based pseudocapacitors use metals that are really expensive and not abundant on earth, while the materials used in this anion-based one uses cheap metals that are abundant in earth’s crust.
—Tyler Mefford, graduate student and lead author
Oak Ridge National Laboratory chemist Sheng Dai developed an energy-storage technology for the project, which received funding from the US Department of Energy’s Office of Science.
Resources
J. Tyler Mefford, William G. Hardin, Sheng Dai, Keith P. Johnston & Keith J. Stevenson (2014) “Anion charge storage through oxygen intercalation in LaMnO3 perovskite pseudocapacitor electrodes” Nature Materials 13, 726–732 doi: 10.1038/nmat4000
I just do not understand electrochemical capacitance.
Anyone?
Isn't leakage a problem?
Posted by: Herman | 31 July 2014 at 09:43 AM
A pseudocapacitor is part of an electrochemical capacitor, and forms together with an electric double-layer capacitor (EDLC) to create a supercapacitor.
A pseudocapacitor has a chemical reaction at the electrode, unlike EDLCs where the electrical charge storage is stored electrostatically with no interaction between the electrode and the ions.
This could mean better supercapacitors.
Posted by: SJC | 31 July 2014 at 09:11 PM