Redox active polymers (RAPs) and Redox Active Colloids (RACs) are emerging as attractive charge storage medium for applications in novel non-aqueous size-excluding flow batteries. Our group demonstrated in 2014 that RAPs can store charge reversibly and be effectively excluded from crossing over a simple nanoporous separator. While increasing the size of the polymer, accessed synthetically in particles ranging from ~4 nm to ~800 nm, should enhance the size exclusion effect for better performing batteries, it also places important constraints on electron transfer. We will discuss on the impact of size and electrolyte interactions on the electrochemistry of RAPs and RACs.<br/><br/>In contrast to the large body of literature existing on polymer films, detailed studies linking polymer structure and dynamics in solution to electrode reactivity are still incipient. Understanding the relationship between solution dynamics and their electrochemical signatures would enable to identify the rate limiting steps in the charge/discharge process in order to design better-performing devices. It is known that ionic electrolyte interactions with charged redox species can dramatically influence the reduction potential and electrochemical kinetics. We have found that ionic interactions, size of electrolyte ions, and the ionic strength can be tuned to systematically enhance the reactivity of poly-nitrostyrene RAPs. Additionally, we will discuss the impact of pendant-to-pendant proximity, colloid size, and electrostatic effects on the transient and steady-state electrochemical behavior of a wide range of polymers in solution and dispersion. Unlike monomers, the electrochemical reactivity of solution-phase polymers is strongly modulated by the properties of both surface confined and freely diffusing polymers in the electrolytes used for size-selective non-aqueous redox flow batteries.

Elucidating the reactivity and solution dynamics of redox active polymers and colloids

253rd National Meeting (2017)

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