Electron Transfer at Low Temperatures: Determining How Electronic Structure and Molecular Shape Affect Reaction Rates

NASA Kentucky Space Grant Research Initiation Award (RIA) project conform to the NASA Education Training Grant purpose by providing early-career faculty and students with the experience of engaging with and understanding NASA's Programs and missions to enable future research opportunities with NASA. The rates of electron transfer in electrochemical energy storage devices are important for designing stsorage systems with high charging rates. For many batteries operated at low temperatures, charging rates are limited and make use in space environments impractical. For example, for travel to the moons of with watery worlds, batteries must charge and discharge effectively at temperatures of -40 ºC and below. NASA's Ocean World Exploration Program involves the exploration of the oceans of the moons Europa and Enceladus, for which abundant water has been found beneath the surfaces. To explore these worlds, low-temperature batteries are needed. Non-aqueous redox flow batteries are a promising technology as organic solvents can be used as electrolytes, allowing these solutions to remain liquid at low temperatures. This proposal will explore the use of organic electro-active materials in the electrolytes of non-aqueous redox flow batteries at low temperatures. We will perform electrochemical analysis of electron-donating and -accepting organic species made in-house at room temperature and below, fabricating a specialized dewar to house electrochemical cells. We will study how the shape and electronic delocalization of the conjugated systems affects the rate of electron transfer at graphitic electrodes and will use that information to determine if any of our materials are candidates for low-temperature redox flow batteries. Promising candidates will be shipped to collaborators at the Jet Propulsion Laboratory for further analysis.