- FUTURE STUDENTS
- FACULTY & STAFF
Friday, April 21, 2017
1-1:50 p.m., Harshbarger 332
The most common approach of improving the power capability of energy storage materials has been to decrease the diffusion distance by nanostructuring. Veronica Augustyn's research explores a different method to improve the kinetics by investigating the effects of structural water in bulk crystalline, layered tungsten oxides. In theory, such materials can offer improved charge transfer at the interface and fast ion transport in the bulk during electrochemical energy storage. Hydrated tungsten oxides are model materials for the systematic investigation of the effect of structural water for high power energy storage because of their stability in acidic and non-aqueous electrolytes, reversible redox, and multiple hydrated phases. The results show that hydrated tungsten oxide exhibits surface-limited (pseudocapacitive) kinetics even with high mass loadings and large crystallite sizes, which leads to high power capability. On the other hand, the anhydrous tungsten oxide exhibits primarily semi-infinite diffusion-controlled kinetics, typical of battery materials. In situ Raman microscopy of the hydrated tungsten oxide points to the presence of reversible proton-induced semiconductor-to-metal transition during electrochemical energy storage. As a result, the hydrated oxides exhibit both fast ion and electron transport. This research identifies an approach for improving power capability in energy storage materials that does not require nanostructuring via the use of interlayer structural water.
Veronica Augustyn, a 2007 graduate of the UA Department of Materials Science and Engineering, is an assistant professor of materials science and engineering at North Carolina State University. She also leads an award-winning international project, SciBridge, which develops renewable energy research and education collaborations between universities in Africa and the United States.