Critical Current Density as a Performance Indicator for Gas-Evolving Electrochemical Devices

Published

August 26, 2020

Author(s)

Jason K. Lee, ChungHyuk Lee, Benzhong Zhao, Jacob LaManna, Eli Baltic, Daniel S. Hussey, David L. Jacobson, Aimy Bazylak

Abstract

Reaching high current densities is absolutely imperative for electrochemical energy conversion, from fuel cells to CO2 reduction. Here, we identify the existence of a performance indicator for gas-evolving electrochemical energy conversion devices: the critical current density. The critical current density pinpoints a performance inflection point whereby both the gas saturations and mass transport overpotentials suddenly dominate cell performance and exacerbate failure. We elucidate the mass transport behavior of a polymer electrolyte membrane (PEM) water electrolyzer using in operando neutron imaging at operating current densities as high as 9 A ⋅ cm−2. Product gases become heterogeneously distributed in the porous transport layer adjacent to the catalyst layer and promote disastrous local hotspots. Optimizing new materials and cell architectures with this performance indicator may unlock higher than previously reported performances for electrochemical energy conversion.

Citation

Cell Reports Physical Science

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.xcrp.2020.100147

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Keywords

Oxygen transport resistance, neutron radiography, electrochemical impedance spectroscopy, mass transport performance

Citation

Lee, J. , Lee, C. , Zhao, B. , LaManna, J. , Baltic, E. , Hussey, D. , Jacobson, D. and Bazylak, A. (2020), Critical Current Density as a Performance Indicator for Gas-Evolving Electrochemical Devices, Cell Reports Physical Science, [online], https://doi.org/10.1016/j.xcrp.2020.100147, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=930353 (Accessed October 10, 2025)