Highly-soluble redox-active polymers (RAPs) and colloids (RACs) have garnered attention recently for their application in size-exclusion redox flow batteries.  The chemistries in these architectures are highly tunable, first by means of appending redox functionality onto them, but also by electrolysis, which modulates the charge on the polymer backbone. Studies on the polyelectrolytic nature of such redox-active macromolecules recently showed that charge transfer mechanisms vary dramatically as a function of the ionic strength and the polymer packing regimes. While traditionally RAPs have been electrochemically studied as films, these new observations on bulk fluids over a broader range of polymer and electrolyte concentrations create new opportunities for the formulation of functional redox fluids. In this presentation, I will discuss new efforts in our laboratory to use the recently discovered charge transfer properties of these fluids for enhancing the rate and directing the reactivity of complex chemistries involved in flowable electrodes. By regarding these polymers not only as charge storage materials, but also as multi-electron transfer redox mediators, exciting possibilities in the modulation of interfacial and solution-mediated processes can be achieved. I will specifically describe our experiments using RAPs to address interface-forming systems with large reaction overpotentials. I will describe the evaluation of RAPs using advanced electroanalytical techniques such as scanning electrochemical microscopy and nanoelectrodes, in addition to voltammetric methods, potential-controlled electrolysis, and spectroelectrochemistry. I will discuss how charge modulation in RAPs as a function of electrolyte concentration an identity can be utilized for modifying interfacial reaction mechanisms for chemistries using conversion chemistries in energy storage. These studies will contribute to discovering strategies for enhancing the rates of complex battery chemistries.

Electrochemical versatility of flowable redox-active polyelectrolytes: Implications for uses beyond energy storage

2019 Spring National Meeting

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