Detection of Free Radical Species in Metal Air Batteries & Organo-Metallic Complexes

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This proposal outlines the need for a benchtop electron paramagnetic resonance (EPR) spectrometer to facilitate characterization of the role and mechanism of reaction of unpaired electrons in a variety of molecules and electrochemical devices. In the context of the popular science, unpaired electrons create the “oxidants” against which “anti-oxidants” work. They are known to be highly reactive and often challenging to characterize. EPR is a perfect tool for such characterization, however EPR instruments used to be large, cumbersome beasts, with high upfront purchase costs. Recently, benchtop EPR spectometers have become available, enabling routine use of such instrumentation at affordable prices. The maintenance is negligible, as are the ongoing operational costs. Therefore, we request funding for a benchtop EPR instrument, to be housed within the nuclear magnetic resonance (NMR) facility at McMaster University, and available to any users of the NMR facility who have received EPR training, (which includes graduate students within the department of chemistry, and faculties of science and engineering), using a nominal user fee structure. Both the Goward and Emslie groups are active research teams, with large groups, who are very keen to have regular access to the data provided by EPR for ongoing projects. In the Emslie group there is an active research program on developing designer molecules that incorporate transition metals, and are utilized to create thin films for microelectronics applications. The research program in the Goward group focuses on the characterization of the lithium and sodium ion transport properties within Li+ and Na+ battery cathode materials, utilizing advanced solid-state NMR. Most recently, the Goward group have investigated a new type of battery materials, the so-called metal-air batteries, in which superoxide radicals are key intermediates in the reaction pathway. An in-house EPR spectrometer would provide direct benefit to both research groups, and would be readily available to students for training and regular use within the research programs described herein.