(Charles W. Tobias Award) Advancing Porous Electrodes for Electrochemical Systems

Abstract

Electrochemical processes are poised to play a pivotal role in the evolving global power system as the efficient interconversion of electrical and chemical energy can enable the deployment of sustainable technologies that support the decarbonization of the electric grid, power the automotive fleet, and offer new opportunities in chemical manufacturing. However, advances in electrochemical science and engineering are needed to address the stringent performance, cost, and scale requirements of these emerging application spaces. Many prominent electrochemical technologies (e.g., flow batteries, fuel cells, electrolyzers) leverage forced convection to increase volumetric productivity. Of particular importance to these systems are porous electrodes which provide surfaces for electrochemical reactions, manage reactant distribution, facilitate mechanical compression, and conduct electrons and heat. Accordingly, the systematic design and engineering of porous electrodes can greatly improve cell performance and durability.In this presentation, I will describe methods for disaggregating and quantifying resistive losses in porous electrodes using redox probes, diagnostic flow cells, and electrochemical modeling. I will then discuss how these tools can be used to guide the design of new electrode architectures with tailored property sets. Specifically, using redox flow batteries as an example, I will offer three vignettes. First, I will discuss the role of electrode microstructure and surface chemistry in balancing electrochemical and fluid dynamic performance within flow cells. Second, building on these results, I will describe efforts to develop electrodes using non-solvent induced phase separation, a synthetic approach which enables property combinations difficult to achieve via current manufacturing processes. Third and finally, I will highlight the potential of conductive particle suspensions as flowable, reconfigurable electrodes whose unusual electrochemical, rheological, and transport properties may unlock more versatile reactor designs.