Check it out…
Nora is a graduate of (the) Ohio State University. Yes, I know, but we still let her in the building. She is our third female Chemical Engineer intern this summer!
Characterization and degradation studies of redox-active organic heterocycles
Nora Shaheen, Nick Mortimer, Shane Mann, and Dr. Thomas Guarr
Protecting batteries from overcharging is critical to prolonging the battery lifetime and preventing dangerous thermal runaway events. Redox shuttles are electrolyte additives that reduce the risk of such events, and therefore help make batteries safer for use. While a myriad of redox shuttles exist, this study focuses predominantly on 9-methyl-3,6-di(t-butyl)carbazole, and 10-methyl-3,7-di(t-butyl)phenothiazine-5,5-dioxide. These heterocycles have shown to be efficient redox shuttles, but further studies into 1) solubility in the desired electrolyte, 2) mass transfer characteristics and limitations, and 3) stability under normal use conditions are necessary. Rotating Disk Electrode (RDE) was used to study the diffusion coefficients of phenothiazine-5,5-dioxides with various N-substituents. Ion Trap Mass Spectrometry (MS) was used to study the gas-phase fragmentation patterns of deuterium-labeled derivatives of these compounds. Lastly, the chemical stability of oxidized 10-methyl-3,7-di(t-butyl)phenothiazine-5,5-dioxide was examined using UV-Vis. The compound was oxidized using bulk electrolysis and through chemical oxidation; preliminary data indicates there are minimal changes in the optical spectrum over time. Further studies are necessary to determine the long-term stability of the oxidized material.
Nora is attending Chemical Engineering graduate school at Case Western Reserve University this fall. We wish her the best and we know she will be amazing.
Bridget is another Chemical Engineer intern this summer from Michigan Technological University. Go Huskies! Bridget performed a great economic analysis of our redox flow battery.
Techno-economic analysis of a nonaqueous redox flow battery with a simple separator.
Bridget O’Connell, Dr. Andre Benard, Korey Cook, Dr. Tom Guarr, Shane Mann
Energy storage is critical for electricity grids that are comprised of intermittent energy sources. Redox flow batteries (RFB) represent a promising method for energy storage and power generation that can be reliable. However, current RFBs lack the capability to meet the demanding $100/kWh requirement established by the Department of Energy (DOE). In this presentation, economic prospects of achievable future cost projections are discussed with the aid of equations and experimental data.
Despite higher chemical costs, employing a chemical system that uses a simple separator, and the implementation of a two-electron transfer system, has reduced the overall capital cost per kWh by 28%. With these changes, the RFB meets the DOE’s target with an overall capital cost of $100.41/kWh. This battery exceeds the DOE’s target of $0.05/kWh for the levelized cost of storage.
Future chemical permutations will be dedicated to reducing molecular weight and material costs. In the end, the impact of these alterations on the overall capital cost per kilowatt-hour, and the LCOS, will drive future research.
Bridget is also returning to MTU and soon will be studying abroad in Chile. (I’m pretty sure I have that right). Thank you for your time this summer Bridget, and thank you for showing that our batteries are economically viable and ready for scale-up!
Over the next few weeks we will be highlighting our summer interns. We had a great summer and we want to thank those that joined us and highlight their accomplishments.
Brittney is a (sophomore!) Chemical Engineering student at Michigan Technological University. She was very busy this summer synthesizing lots of compounds.
Synthesis of phenylene-bridged bispyridine derivatives
Brittney Duford, Shane Mann, Nick Mortimer, Dr. Thomas Guarr
Numerous substituted phenylene-bridged bispyridine derivatives were synthesized as a method of improving solubility and electroactivity of compounds prepared from these materials. Such compounds are used as redox-active materials in redox flow batteries. Redox flow batteries show promise to better our ability to store large amounts of energy, as long as the compounds within the battery’s electrolyte solution are stable, have high energy densities, and maintain low production costs. Improved solubility and electroactivity was achieved by adding methyl substituents to the phenyl group and changing the orientation of the pyridine groups in relation to each other. Five different derivatives were synthesized via a double Suzuki coupling process followed by N-methylation. Each was characterized by NMR and cyclic voltammetry. Characterization showed increased solubility and better electroactivity for some derivatives. The improved derivatives will be incorporated into linked systems previously developed for electrolyte solutions in redox flow batteries. The linked systems will then be compared to previous linked systems and tested for stability.
Brittney is returning to MTU this fall. Thanks for joining us and thanks for working so hard this summer. Your future is bright. Stay warm in Houghton!
Once again, we are grateful for our friends at Hope College and their generous offer to allow our interns to present their posters at the 2018 Hope College research symposium on July 13. Brittney Duford, Bridget O’Connell and Nora Shaheen presented their posters representing the research they have completed during the summer here at the Organic Energy Storage Laboratory.
More information on our interns, their research and their posters coming soon.
Tom was interviewed by Scott Pohl from WKAR, an NPR station, about his cutting-edge work with battery energy storage and battery over-charge prevention.
Take a listen!