Elucidating the Impact of Conductive Additives on Redox-mediated Reactions through a Porous Electrode Theory Approach
Year: 2026
Type: preprint
Abstract: *Corresponding Author Abstract While common to redox-mediated flow batteries (RMFBs), the role and influence of conductive composites vary widely, obfuscating pathways for performance improvements. In this work, we expand upon an earlier modeling framework to explicitly resolve the charge transport within composite active materials of RMFBs, combining porous electrode and mixed potential theories to describe the internal currents and charge transfer reactions produced by the “off-electrode” chemical redox reactions. The derived models elucidate the dynamics and spatial distributions of the mediator and solid half-reactions, highlighting differences in the driving force and mediator reaction rate associated with the active solid and conductive solid interfaces. The importance of conductive additives is found to be strongly tied to the relative rates of the active solid and “localized” mediator half-reactions occurring at the active solid interface, providing an explanation for the observed discrepancies in the observed improvements. A previously derived scaling relationship is adapted to capture trends in solid utilization for composite active materials in RMFBs. Together, these advancements provide newfound insights, offering guidance into the design and study of emerging redox-mediated systems.
Source: ChemRxiv
Authors: Nicholas J. Matteucci, Fikile R. Brushett
Institution: Massachusetts Institute of Technology
Language: English
Topic: Aqueous and Flow Batteries
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Funder: National Science Foundation
OpenAlex ID: W7204795292