Leininger, Sara; Minteer, Shelley; Rhodes, Zayn; Sigman, Matt; Pancoast, Adam (University of Utah)
Faculty Advisor: Minteer, Shelley (University of Utah College of Science, Chemisty)
In the effort to improve renewable energy as a response to the depletion of fossil fuels, one important aspect to consider is the availability of such sources. The supply of solar and wind power, for example, faces issues with intermittency. Therefore, it is crucial to develop reliable energy storage methods, with redox flow batteries (RFBs) being of particular interest given their potential low cost and high efficiency. RFBs operate similarly to conventional batteries, except the anode and cathode materials are dissolved in electrolyte solutions, and pumped into the electrochemical cell from external storage tanks. Within the cell, the anode and cathode species are separated by a membrane to prevent them from mixing, which would cause the battery to self-discharge. RFBs can utilize aqueous- or organic-based electrolyte solutions, with organic solvents being especially appealing, as the electrochemical potential window is larger than water. However, one major impediment of using organic solvent is the high chemical crossover rate of anode and cathode species through the membrane, causing rapid capacity fade of the battery. Several research studies have shown that the use of redox active polymers (RAPs) with high molecular weights, paired with a size-exclusion membrane effectively counteracts this problem. The resulting steric hindrance between the small pores of the membrane and these large molecules blocks any crossover from the active species. This study will include the construction of an RFB using two previously developed RAPs demonstrated to have high electrochemical cycling stability as electrolytes. By using RAPs as both anode and cathode materials, it is expected that chemical crossover will be minimized, and the lifetime of the battery will be elongated compared to an RFB with one or both species in monomeric form. This study will be significant in the advancement of RFBs, potentially leading to their widespread use for energy storage.