Critical Current Density as a Performance Indicator for Gas-Evolving Electrochemical Devices
Jason K. Lee, ChungHyuk Lee, Benzhong Zhao, Jacob LaManna, Eli Baltic, Daniel S. Hussey, David L. Jacobson, Aimy Bazylak
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.
, Lee, C.
, Zhao, B.
, LaManna, J.
, Baltic, E.
, Hussey, D.
, Jacobson, D.
and Bazylak, A.
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 December 4, 2023)