Nonaqueous redox flow batteries promise a dramatic increase in energy density in comparison to aqueous technologies, in great part owing to a wider potential window of accessible redoxmers. Understanding the unique challenges of the nonaqueous solvent/electrode interface is key in developing batteries with high performance and long-term stability. During the development of redoxmers for nonaqueous flow batteries, a significant emphasis has been placed on designing redoxmers with superior stability in solution. However, heterogeneous aspects of redoxmer cycling, such as redoxmer adsorption, electrode fouling, the formation of rate-limiting interfaces, and the production of reactive intermediates at highly polarized electrodes can be equally important in ensuring the success of the battery. Thus, it is desirable to develop an experimental and theoretical toolset capable of correlating performance improvements and losses during redoxmer cycling to their heterogeneous reactivity at electrodes. <br/>In this talk, we will discuss an approach based on scanning electrochemical microscopy to measure and characterize the rate of redoxmer heterogeneous kinetics at metals and at modified atomically thin carbon electrodes. Based on previous knowledge of the formation of adsorbed redoxmer layers in selected nonaqueous systems, we hypothesized that redoxmer adsorption energies on modified graphene interfaces could help explain differences in the rate of electron transfer. By modifying graphene electrodes using a variety of reactive plasmas, and comparing their reactivity with metals and pristine graphene electrodes, we found that in certain cases reactive trends correlate with predicted adsorption energies. We will discuss the validation aspects and limitations of our approach in linking cycling performance with phenomena occurring at electrode surfaces.

Probing the role of adsorption, passivation, and surface functionalization on the heterogeneous electrochemical reactivity of redoxmers for redox flow battery applications

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.