Triply Periodic Minimal Surfaces as Additive Manufactured Metal Electrodes: Assessment through a Hydrodynamic Electrode Performance Factor

Abstract

This work applies a hydrodynamic electrode performance factor (HEPF) to evaluate triply periodic minimal surface (TPMS) porous electrodes in electrochemical flow reactors. Traditional approaches to electrode characterization and optimization treat mass transfer and pressure drop as separate metrics, complicating comparisons. To address this, these parameters are integrated into a unified mathematical expression inspired by established heat transfer equations and the Chilton–Colburn analogy. The HEPF provides an alternative method to assess electrode performance, complementing the volumetric mass transfer coefficient, and Storck's energetic effectiveness principle for electrochemical reactors. Stainless steel 316 L TPMS electrodes with 60% target porosity are fabricated using additive manufacturing, their mass transfer and pressure drop analyzed experimentally. Mass transfer is determined from single-pass ferricyanide ion reduction rates measured using UV-vis spectroscopy. Pressure drop is measured directly across electrodes at various flow rates. Results demonstrated that TPMS structures, particularly the Schwarz-D, can achieve superior performance as porous electrodes by combining high surface area and mass transfer with low pressure drop. This study highlights the significance of integrating performance factors in electrode design, featuring the HEPF as a viable method for optimizing advanced electrodes for industrial applications.