NSF Award
1409102
NON-TECHNICAL DESCRIPTION: New and improved approaches to storing electrical energy are critical for hand-held electronics and for integrating new renewable energy sources into our electrical power grid. The research focus is on finding new ways of improving the amount of energy stored in a battery or capacitor by intentionally introducing atomic-scale defects into ceramic nanosheets that form the electrodes. The ceramic nanosheets of interest are remarkably thin - only 5-10 atoms - and they display unusual properties for storing energy, resulting in better capacitors (called supercapacitors that bridge the gap between conventional capacitors and rechargeable batteries). Using new methods to measure the structural defects in the thin ceramic nanosheets and combining that knowledge with the measured electrical storage behavior provides a path to engineering new supercapacitors that may transform the way we use traditional and renewable energy sources. The project includes a team of two graduate students and two undergraduate students and reaches campus visitors of all ages who participate in the Kyocera Museum programs.<br/><br/>TECHNICAL DETAILS: The overall technical objective is to provide the first quantitative assessment of the electrochemical effects of intentional cation defects on proton intercalation in model single-layer nanosheet systems for Faradaic supercapacitors. Model systems include nanosheets of MnO6 and VO6 octahedra, where large fractions of octahedral defects, up to 20%, may be introduced during synthesis. The cation defects include charged metal ion vacancies and MO6 octahedra that are displaced from the otherwise atomically-flat nanosheet. The defects form new proton adsorption and intercalation sites that may markedly increase the energy storage capacity. New X-ray scattering methods enable direct study of the defects in nanosheets, and the model single-layer nanosheet structure provides a platform to determine the unknown roles of defects in pseudocapacitive charge storage. The latter may be transformational by defining the ideal nano- and meso-scale structures to facilitate commercialization of supercapacitors.
