Estimating charge-transport properties of fuel-cell and electrolyzer catalyst layers via electrochemical impedance spectroscopy

Kosakian, Aslan; Secanell, Marc

doi:10.1016/j.electacta.2020.137521

Cited by 35 publications

(25 citation statements)

References 103 publications

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“…To further reveal the internal change of the cell after the durability test, EIS has been introduced to analyze the ionic resistance change of the anion exchange membrane (R mem ) and the catalytic layer (R CL ). As shown in Figure b, the impedance behavior under the open-circuit condition of the cell is similar to the transmission line model. − The intersection of the high-frequency part of the EIS and the real axis is considered as the R mem , , and the intersection of the extension line of the low-frequency oblique line and the real axis is considered as the sum of the R mem and one-third of the R CL . , The results in Figure b show that after the stability test, the R mem barely changed, but the R CL (the sum of the catalytic layer resistance of both anode and cathode) increased significantly from 0.38 to 0.77 Ω·cm 2 . Since R CL is undertaken by the ionomer and the external electrolyte (KOH in this case), , and the KOH concentration has not changed during the test, we believe the increase of R CL after the durability test should be ascribed to the conductivity loss of the ionomer.…”

Section: Resultsmentioning

confidence: 83%

Impact of Catalyst Reconstruction on the Durability of Anion Exchange Membrane Water Electrolysis

Lei

Yang

Wang

et al. 2022

ACS Sustainable Chem. Eng.

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Anion exchange membrane water electrolysis (AEMWE) offers an opportunity to use inexpensive nonprecious metal catalysts. However, pure water-fed AEMWE still faces issues of durability. Herein, we compared the stability of AEMWE under different anolytes, including KOH, pure water, and a phosphate buffer (PB) using a NiFeCo oxygen evolution reaction catalyst. Upon thoroughly characterizing several changes before/after 100 h durability tests, such as the cell performance, catalyst dissolution, catalyst morphologies, impedance of the anion exchange membrane, and catalytic layer, we speculate that the change of the local pH is the main factor causing catalyst reconstruction, which further leads to the loss of cell performance in the pure water-fed mode. By using PB to control the local pH, the morphology of the catalyst will no longer change after the durability test, and the cell performance can recover to the initial performance in pure water. These results not only indicate that the catalyst structural transformation is the main reason for the deactivation of pure water-fed AEMWE but also help find a way to achieve highly durable pure water-fed AEMWE.

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Section: Resultsmentioning

confidence: 83%

Impact of Catalyst Reconstruction on the Durability of Anion Exchange Membrane Water Electrolysis

Lei

Yang

Wang

et al. 2022

ACS Sustainable Chem. Eng.

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“…The fitting results unveiled that the C dl,hf increased by 1652%, from 2.3 to 40.3 mF cm –2 , and the R ct,hf decreased almost 50%, from 118.9 to 62.1 mΩ cm 2 . The C dl value is the capacity between the electrode and electrolyte interface, which is related to the number of reaction sites (active area) closely. , At the whole-cell level, the dramatic increase of C dl,hf indicates that more reaction sites were activated during conditioning. The fully conditioned MEA increased the active reaction sites.…”

Section: Resultsmentioning

confidence: 99%

Exploring the Impacts of Conditioning on Proton Exchange Membrane Electrolyzers by In Situ Visualization and Electrochemistry Characterization

Wang

Ding

et al. 2022

ACS Appl. Mater. Interfaces

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For a proton exchange membrane electrolyzer cell (PEMEC), conditioning is an essential process to enhance its performance, reproducibility, and economic efficiency. To get more insights into conditioning, a PEMEC with Ir-coated gas diffusion electrode (IrGDE) was investigated by electrochemistry and in situ visualization characterization techniques. The changes of polarization curves, electrochemical impedance spectra (EIS), and bubble dynamics before and after conditioning are analyzed. The polarization curves show that the cell efficiency increased by 9.15% at 0.4 A/cm2, and the EIS and Tafel slope results indicate that both the ohmic and activation overpotential losses decrease after conditioning. The visualization of bubble formation unveils that the number of bubble sites increased greatly from 14 to 29 per pore after conditioning, at the same voltage of 1.6 V. Under the same current density of 0.2 A/cm2; the average bubble detachment size decreased obviously from 35 to 25 μm. The electrochemistry and visualization characterization results jointly unveiled the increase of reaction sites and the surface oxidation on the IrGDE during conditioning, which provides more insights into the conditioning and benefits for the future GDE design and optimization.

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“…The ohmic resistance between the electrolyte and electrode is described by the intersection of the semicircle and the real axis in the high frequency region [ 26 ]. The charged electron transfer resistance is depicted by the slope of the line in the middle frequency region [ 27 ]. The curves illustrate that the DCT-12 had better electrochemical performance than the others.…”

Section: Resultsmentioning

confidence: 99%

Effects of Deep Cryogenic Treatment on the Microstructure and Properties of Rolled Cu Foil

et al. 2021

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The development of fifth-generation (5G) communication and wearable electronics generates higher requirements for the mechanical properties of copper foil. Higher mechanical properties and lower resistance are required for flexible copper-clad laminate and high-frequency and high-speed Cu foil. Deep cryogenic treatment (DCT), as a post-treatment method, has many advantages, such as low cost and ease of operation. However, less attention has been paid to the impact of DCT on rolled Cu foil. In this study, the effects of DCT on the microstructure and mechanical properties of rolled Cu foil were investigated. The results show that as the treatment time increased, the tensile strength and hardness first increased and then decreased, reaching a peak value of 394.06 MPa and 1.47 GPa at 12 h. The mechanical property improvement of rolled Cu foil was due to the grain refinement and the increase of dislocation density. The dislocation density of rolled Cu foil after a DCT time of 12 h was determined to have a peak value of 4.3798 × 1015 m−2. The dislocation density increased by 19% and the grain size decreased by 12% after 12 h DCT.

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Estimating charge-transport properties of fuel-cell and electrolyzer catalyst layers via electrochemical impedance spectroscopy

Cited by 35 publications

References 103 publications

Impact of Catalyst Reconstruction on the Durability of Anion Exchange Membrane Water Electrolysis

Impact of Catalyst Reconstruction on the Durability of Anion Exchange Membrane Water Electrolysis

Exploring the Impacts of Conditioning on Proton Exchange Membrane Electrolyzers by In Situ Visualization and Electrochemistry Characterization

Effects of Deep Cryogenic Treatment on the Microstructure and Properties of Rolled Cu Foil

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