---
_id: '62814'
abstract:
- lang: eng
  text: Porous carbons are prominent electrode materials in energy storage applications
    such as supercapacitors. However, rational materials development is hampered by
    difficulties in interpreting electrochemical impedance spectra (EIS) and drawing
    conclusions about promising aspects of device improvement. Here, we characterized
    electrodes consisting of activated carbon with polyacrylic acid binder in four
    different concentrations of sulfuric acid, using cyclic voltammetry and electrochemical
    impedance spectroscopy. Both datasets were evaluated with simple equivalent circuits
    and comparatively analyzed. Conductivity of the electrolyte was independently
    measured. Cyclic voltammograms (CV) show larger resistance and capacitance at
    low scan rates. Resistances obtained from EIS are in good agreement with those
    obtained by cyclic voltammograms particularly at high scan rates. The comparison
    against specific electrolyte resistance can reveal whether resistances within
    the solid electrode architecture or resistances within the electrolyte, partially
    confined by pores, are the dominant cause of increased resistance at low scan
    rate. Comparison between CV and EIS points to the main electrode capacitance being
    described by a constant phase element (CPE) used to fit the low-frequency region
    of EIS.
author:
- first_name: Sebastian
  full_name: Reinke, Sebastian
  id: '117727'
  last_name: Reinke
- first_name: Vera
  full_name: Khamitsevich, Vera
  last_name: Khamitsevich
- first_name: Julia
  full_name: Linnemann, Julia
  id: '116779'
  last_name: Linnemann
  orcid: 0000-0001-6883-5424
citation:
  ama: 'Reinke S, Khamitsevich V, Linnemann J. Complementary Analysis of Cyclic Voltammograms
    and Impedance Spectra of Porous Carbon Electrodes. In: <i>2024 International Workshop
    on Impedance Spectroscopy (IWIS)</i>. IEEE; 2025. doi:<a href="https://doi.org/10.1109/iwis63047.2024.10847115">10.1109/iwis63047.2024.10847115</a>'
  apa: Reinke, S., Khamitsevich, V., &#38; Linnemann, J. (2025). Complementary Analysis
    of Cyclic Voltammograms and Impedance Spectra of Porous Carbon Electrodes. <i>2024
    International Workshop on Impedance Spectroscopy (IWIS)</i>. <a href="https://doi.org/10.1109/iwis63047.2024.10847115">https://doi.org/10.1109/iwis63047.2024.10847115</a>
  bibtex: '@inproceedings{Reinke_Khamitsevich_Linnemann_2025, title={Complementary
    Analysis of Cyclic Voltammograms and Impedance Spectra of Porous Carbon Electrodes},
    DOI={<a href="https://doi.org/10.1109/iwis63047.2024.10847115">10.1109/iwis63047.2024.10847115</a>},
    booktitle={2024 International Workshop on Impedance Spectroscopy (IWIS)}, publisher={IEEE},
    author={Reinke, Sebastian and Khamitsevich, Vera and Linnemann, Julia}, year={2025}
    }'
  chicago: Reinke, Sebastian, Vera Khamitsevich, and Julia Linnemann. “Complementary
    Analysis of Cyclic Voltammograms and Impedance Spectra of Porous Carbon Electrodes.”
    In <i>2024 International Workshop on Impedance Spectroscopy (IWIS)</i>. IEEE,
    2025. <a href="https://doi.org/10.1109/iwis63047.2024.10847115">https://doi.org/10.1109/iwis63047.2024.10847115</a>.
  ieee: 'S. Reinke, V. Khamitsevich, and J. Linnemann, “Complementary Analysis of
    Cyclic Voltammograms and Impedance Spectra of Porous Carbon Electrodes,” 2025,
    doi: <a href="https://doi.org/10.1109/iwis63047.2024.10847115">10.1109/iwis63047.2024.10847115</a>.'
  mla: Reinke, Sebastian, et al. “Complementary Analysis of Cyclic Voltammograms and
    Impedance Spectra of Porous Carbon Electrodes.” <i>2024 International Workshop
    on Impedance Spectroscopy (IWIS)</i>, IEEE, 2025, doi:<a href="https://doi.org/10.1109/iwis63047.2024.10847115">10.1109/iwis63047.2024.10847115</a>.
  short: 'S. Reinke, V. Khamitsevich, J. Linnemann, in: 2024 International Workshop
    on Impedance Spectroscopy (IWIS), IEEE, 2025.'
date_created: 2025-12-03T16:06:09Z
date_updated: 2026-01-19T15:41:43Z
department:
- _id: '985'
doi: 10.1109/iwis63047.2024.10847115
extern: '1'
keyword:
- electrochemical impedance spectroscopy
- distorted cyclic voltammograms
- supercapacitors
- carbon
language:
- iso: eng
publication: 2024 International Workshop on Impedance Spectroscopy (IWIS)
publication_status: published
publisher: IEEE
quality_controlled: '1'
status: public
title: Complementary Analysis of Cyclic Voltammograms and Impedance Spectra of Porous
  Carbon Electrodes
type: conference
user_id: '116779'
year: '2025'
...
---
_id: '62812'
abstract:
- lang: eng
  text: Attributing features of electrochemical impedance spectra to electrochemical
    phenomena is both crucial and frequently ambiguous. To elucidate the origin of
    the ohmic part of the spectrum, activated carbon electrodes were prepared with
    different contents of polyacrylic acid as binder. Their impedance spectra and
    cyclic voltammograms were recorded using sulfuric acid of five different concentrations
    as the electrolyte. To distinguish electrolyte resistance and resistances related
    to the activated carbon layer of the electrode, the specific electrolyte conductivity
    was independently measured and compared against the ohmic part of the electrochemical
    impedance spectra (EIS). The capacitive cyclic voltammograms show larger resistive
    contributions with higher scan rate and lower electrolyte conductivity. Comparing
    the ohmic part of the EIS to the specific resistance of the electrolyte, a linear
    function with no statistically significant offset was found. The ohmic part of
    the EIS, thus, reflects the electrolyte resistance, not that of the carbon electrode.
author:
- first_name: Sebastian
  full_name: Reinke, Sebastian
  id: '117727'
  last_name: Reinke
- first_name: Vera
  full_name: Khamitsevich, Vera
  last_name: Khamitsevich
- first_name: Oliver
  full_name: Röth, Oliver
  id: '117786'
  last_name: Röth
- first_name: Julia
  full_name: Linnemann, Julia
  id: '116779'
  last_name: Linnemann
  orcid: 0000-0001-6883-5424
citation:
  ama: 'Reinke S, Khamitsevich V, Röth O, Linnemann J. Assessment of the Physicochemical
    Meaning of the Ohmic Series Resistance Observed for High Frequencies in Electrochemical
    Impedance Spectra. In: <i>2023 International Workshop on Impedance Spectroscopy
    (IWIS)</i>. IEEE; 2023. doi:<a href="https://doi.org/10.1109/iwis61214.2023.10302764">10.1109/iwis61214.2023.10302764</a>'
  apa: Reinke, S., Khamitsevich, V., Röth, O., &#38; Linnemann, J. (2023). Assessment
    of the Physicochemical Meaning of the Ohmic Series Resistance Observed for High
    Frequencies in Electrochemical Impedance Spectra. <i>2023 International Workshop
    on Impedance Spectroscopy (IWIS)</i>. <a href="https://doi.org/10.1109/iwis61214.2023.10302764">https://doi.org/10.1109/iwis61214.2023.10302764</a>
  bibtex: '@inproceedings{Reinke_Khamitsevich_Röth_Linnemann_2023, title={Assessment
    of the Physicochemical Meaning of the Ohmic Series Resistance Observed for High
    Frequencies in Electrochemical Impedance Spectra}, DOI={<a href="https://doi.org/10.1109/iwis61214.2023.10302764">10.1109/iwis61214.2023.10302764</a>},
    booktitle={2023 International Workshop on Impedance Spectroscopy (IWIS)}, publisher={IEEE},
    author={Reinke, Sebastian and Khamitsevich, Vera and Röth, Oliver and Linnemann,
    Julia}, year={2023} }'
  chicago: Reinke, Sebastian, Vera Khamitsevich, Oliver Röth, and Julia Linnemann.
    “Assessment of the Physicochemical Meaning of the Ohmic Series Resistance Observed
    for High Frequencies in Electrochemical Impedance Spectra.” In <i>2023 International
    Workshop on Impedance Spectroscopy (IWIS)</i>. IEEE, 2023. <a href="https://doi.org/10.1109/iwis61214.2023.10302764">https://doi.org/10.1109/iwis61214.2023.10302764</a>.
  ieee: 'S. Reinke, V. Khamitsevich, O. Röth, and J. Linnemann, “Assessment of the
    Physicochemical Meaning of the Ohmic Series Resistance Observed for High Frequencies
    in Electrochemical Impedance Spectra,” 2023, doi: <a href="https://doi.org/10.1109/iwis61214.2023.10302764">10.1109/iwis61214.2023.10302764</a>.'
  mla: Reinke, Sebastian, et al. “Assessment of the Physicochemical Meaning of the
    Ohmic Series Resistance Observed for High Frequencies in Electrochemical Impedance
    Spectra.” <i>2023 International Workshop on Impedance Spectroscopy (IWIS)</i>,
    IEEE, 2023, doi:<a href="https://doi.org/10.1109/iwis61214.2023.10302764">10.1109/iwis61214.2023.10302764</a>.
  short: 'S. Reinke, V. Khamitsevich, O. Röth, J. Linnemann, in: 2023 International
    Workshop on Impedance Spectroscopy (IWIS), IEEE, 2023.'
date_created: 2025-12-03T15:58:28Z
date_updated: 2026-01-19T15:40:41Z
department:
- _id: '985'
doi: 10.1109/iwis61214.2023.10302764
extern: '1'
keyword:
- electrochemical impedance spectroscopy
- supercapacitors
- carbon
language:
- iso: eng
publication: 2023 International Workshop on Impedance Spectroscopy (IWIS)
publication_status: published
publisher: IEEE
quality_controlled: '1'
status: public
title: Assessment of the Physicochemical Meaning of the Ohmic Series Resistance Observed
  for High Frequencies in Electrochemical Impedance Spectra
type: conference
user_id: '116779'
year: '2023'
...
---
_id: '62801'
abstract:
- lang: eng
  text: The three-dimensional (3D) distribution of individual atoms on the surface
    of catalyst nanoparticles plays a vital role in their activity and stability.
    Optimising the performance of electrocatalysts requires atomic-scale information,
    but it is difficult to obtain. Here, we use atom probe tomography to elucidate
    the 3D structure of 10 nm sized Co2FeO4 and CoFe2O4 nanoparticles during oxygen
    evolution reaction (OER). We reveal nanoscale spinodal decomposition in pristine
    Co2FeO4. The interfaces of Co-rich and Fe-rich nanodomains of Co2FeO4 become trapping
    sites for hydroxyl groups, contributing to a higher OER activity compared to that
    of CoFe2O4. However, the activity of Co2FeO4 drops considerably due to concurrent
    irreversible transformation towards CoIVO2 and pronounced Fe dissolution. In contrast,
    there is negligible elemental redistribution for CoFe2O4 after OER, except for
    surface structural transformation towards (FeIII, CoIII)2O3. Overall, our study
    provides a unique 3D compositional distribution of mixed Co-Fe spinel oxides,
    which gives atomic-scale insights into active sites and the deactivation of electrocatalysts
    during OER.
article_number: '179'
article_type: original
author:
- first_name: Weikai
  full_name: Xiang, Weikai
  last_name: Xiang
- first_name: Nating
  full_name: Yang, Nating
  last_name: Yang
- first_name: Xiaopeng
  full_name: Li, Xiaopeng
  last_name: Li
- first_name: Julia
  full_name: Linnemann, Julia
  id: '116779'
  last_name: Linnemann
  orcid: 0000-0001-6883-5424
- first_name: Ulrich
  full_name: Hagemann, Ulrich
  last_name: Hagemann
- first_name: Olaf
  full_name: Ruediger, Olaf
  last_name: Ruediger
- first_name: Markus
  full_name: Heidelmann, Markus
  last_name: Heidelmann
- first_name: Tobias
  full_name: Falk, Tobias
  last_name: Falk
- first_name: Matteo
  full_name: Aramini, Matteo
  last_name: Aramini
- first_name: Serena
  full_name: DeBeer, Serena
  last_name: DeBeer
- first_name: Martin
  full_name: Muhler, Martin
  last_name: Muhler
- first_name: Kristina
  full_name: Tschulik, Kristina
  last_name: Tschulik
- first_name: Tong
  full_name: Li, Tong
  last_name: Li
citation:
  ama: Xiang W, Yang N, Li X, et al. 3D atomic-scale imaging of mixed Co-Fe spinel
    oxide nanoparticles during oxygen evolution reaction. <i>Nature Communications</i>.
    2022;13(1). doi:<a href="https://doi.org/10.1038/s41467-021-27788-2">10.1038/s41467-021-27788-2</a>
  apa: Xiang, W., Yang, N., Li, X., Linnemann, J., Hagemann, U., Ruediger, O., Heidelmann,
    M., Falk, T., Aramini, M., DeBeer, S., Muhler, M., Tschulik, K., &#38; Li, T.
    (2022). 3D atomic-scale imaging of mixed Co-Fe spinel oxide nanoparticles during
    oxygen evolution reaction. <i>Nature Communications</i>, <i>13</i>(1), Article
    179. <a href="https://doi.org/10.1038/s41467-021-27788-2">https://doi.org/10.1038/s41467-021-27788-2</a>
  bibtex: '@article{Xiang_Yang_Li_Linnemann_Hagemann_Ruediger_Heidelmann_Falk_Aramini_DeBeer_et
    al._2022, title={3D atomic-scale imaging of mixed Co-Fe spinel oxide nanoparticles
    during oxygen evolution reaction}, volume={13}, DOI={<a href="https://doi.org/10.1038/s41467-021-27788-2">10.1038/s41467-021-27788-2</a>},
    number={1179}, journal={Nature Communications}, publisher={Springer Science and
    Business Media LLC}, author={Xiang, Weikai and Yang, Nating and Li, Xiaopeng and
    Linnemann, Julia and Hagemann, Ulrich and Ruediger, Olaf and Heidelmann, Markus
    and Falk, Tobias and Aramini, Matteo and DeBeer, Serena and et al.}, year={2022}
    }'
  chicago: Xiang, Weikai, Nating Yang, Xiaopeng Li, Julia Linnemann, Ulrich Hagemann,
    Olaf Ruediger, Markus Heidelmann, et al. “3D Atomic-Scale Imaging of Mixed Co-Fe
    Spinel Oxide Nanoparticles during Oxygen Evolution Reaction.” <i>Nature Communications</i>
    13, no. 1 (2022). <a href="https://doi.org/10.1038/s41467-021-27788-2">https://doi.org/10.1038/s41467-021-27788-2</a>.
  ieee: 'W. Xiang <i>et al.</i>, “3D atomic-scale imaging of mixed Co-Fe spinel oxide
    nanoparticles during oxygen evolution reaction,” <i>Nature Communications</i>,
    vol. 13, no. 1, Art. no. 179, 2022, doi: <a href="https://doi.org/10.1038/s41467-021-27788-2">10.1038/s41467-021-27788-2</a>.'
  mla: Xiang, Weikai, et al. “3D Atomic-Scale Imaging of Mixed Co-Fe Spinel Oxide
    Nanoparticles during Oxygen Evolution Reaction.” <i>Nature Communications</i>,
    vol. 13, no. 1, 179, Springer Science and Business Media LLC, 2022, doi:<a href="https://doi.org/10.1038/s41467-021-27788-2">10.1038/s41467-021-27788-2</a>.
  short: W. Xiang, N. Yang, X. Li, J. Linnemann, U. Hagemann, O. Ruediger, M. Heidelmann,
    T. Falk, M. Aramini, S. DeBeer, M. Muhler, K. Tschulik, T. Li, Nature Communications
    13 (2022).
date_created: 2025-12-03T15:22:16Z
date_updated: 2025-12-03T16:30:12Z
department:
- _id: '985'
doi: 10.1038/s41467-021-27788-2
extern: '1'
intvolume: '        13'
issue: '1'
keyword:
- electrocatalysis
- oxygen evolution reaction
- cobalt spinel
- electrochemical impedance spectroscopy
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://www.nature.com/articles/s41467-021-27788-2
oa: '1'
publication: Nature Communications
publication_identifier:
  issn:
  - 2041-1723
publication_status: published
publisher: Springer Science and Business Media LLC
quality_controlled: '1'
status: public
title: 3D atomic-scale imaging of mixed Co-Fe spinel oxide nanoparticles during oxygen
  evolution reaction
type: journal_article
user_id: '116779'
volume: 13
year: '2022'
...