Flow-Directing Electrodes with Multi-Scale Porosity for Controlling Transport and Reactions

Systems that simultaneously optimize transport and reaction parameters are crucial for chemical process intensification. In this talk, we discuss recent progress towards additively manufactured electrode materials that control flow fields in electrochemical systems with forced convection, coined “flow-directing electrodes.” We show how 3D printed micro-scale architected structures formed from metal-coated polymers, pure metals/oxides, or pyrolytic carbon can tune flow properties and prevent fouling in electrochemical systems while simultaneously providing pathways for electron transfer. We additionally show how to create multiscale hierarchy through the incorporation of nano-scale porosity in these systems via ZnO nanorod templating to tune specific surface area and permeability. We demonstrate the utility of such flow-directing electrodes for applications ranging from electrochemical remediation of per- and poly-fluoroalkyl substances (PFAS) where a nano-porous layer could act as a size-exclusion membrane to design of electrodes for redox-flow batteries where transport of working ions and redox-active material is maximized but transport and crossover of other species such as electrolytes and mediators is minimized. Flow-directing electrodes represent a paradigm shift in electrochemical reactor design in which high resolution vat photopolymerization printing techniques are used to create co-designed structures with complex geometry using electrically conductive functional materials—all leading to the ability to explore a wide landscape of previously impossible device designs.