Non-aqueous redox flow batteries (NaRFBs) are a promising technology for widespread grid-scale energy storage deployment. Despite their potential for high energy density, current active materials lack the necessary stability and cyclability for scale-up. One class of active materials for NaRFBs are redox active organic molecules (ROMs), which are a focus of recent development due to their low cost and high solubilities compared to other candidate active materials. The research in this thesis seeks to advance of ROM development through characterization of new active materials and development of computational design tools for stability and cyclability. ROM characterization focused on cyclability of the dialkoxyarene ROM catholyte family and (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO). An extensive set of bulk electrolysis (BE) experiments with varying active material concentration, cycle rate, and supporting salt were performed. Two different design strategies for improving dialkoxyarene cyclability were identified: increasing steric hinderance in alkylammonium electrolytes and increasing lithium-coordination in lithium electrolytes. These two strategies and the BE data provide new insight into ROM design and proper selection of electrolytes for cyclability. Computational work used the model building tool Sure Independence Screening and Sparsifying Operator (SISSO) to develop models for screening and prediction of ROMs. A variety of prediction tools for dialkoxyarene and TEMPO cyclability were developed, highlighting the lowest unoccupied molecular orbital (LUMO) energy and the solvation energy as the most important active material descriptors for improving cyclability. Similar tools were developed for dialkoxyarene stability, with the LUMO energy and geometry as the most important factors identified by SISSO. Most significantly, a generalized screening model for stability was developed from data for dialkoxyarene catholytes and pyridinium anolytes. This model is the first generalizable model for any ROM property of interest and provides insight into the unknown factors affecting electrochemical stability. These models provide foundations and methods for the computational design of new ROMs.PHDChemical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/167994/1/bsilcox_1.pd
