Redox effect of Fe2+/Fe3+ in iron phosphates for enhanced electrocatalytic activity in Li-O2 batteries

Gwang Hee Lee, Yoon Seon Kim, Dong Wan Kim

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


FePO4 and porous Fe2P2O7 laundry-ball-like nanostructures (FePO4 LBs and p-Fe2P2O7 LBs, respectively) were prepared to investigate their functionalities as oxygen-electrode (O2-electrode) electrocatalysts in Li–O2 batteries. These structures were synthesized in two steps, via hydrothermal and thermal reactions. FePO4 LBs were synthesized through thermal dehydrogenation of as-prepared FePO4·2H2O precursors (FePO4·2H2O → FePO4 + 2H2O), and p-Fe2P2O7 LBs were synthesized through thermochemical reduction of same precursors under an H2 atmosphere (2FePO4·2H2O + H2 → Fe2P2O7 + 5H2O). As an O2-electrode electrocatalyst in Li–O2 cells, p-Fe2P2O7 LBs exhibited a higher discharge capacity (30,000 mA h gcatalyst–1 at a current density of 500 mA gcatalyst–1), higher reversibility (300 cycles at a current rate of 500 mA gcatalyst–1), and lower voltage gap, compared to FePO4 LBs. These superior performances of p-Fe2P2O7 LBs result from the Fe2+/Fe3+ redox effect and porous structure, which enhance the oxygen reduction or evolution reaction activities.

Original languageEnglish
Article number124294
JournalChemical Engineering Journal
Publication statusPublished - 2020 May 15

Bibliographical note

Funding Information:
This work was supported by a Korea University Grant, South Korea and, the National Research Foundation of Korea (NRF) Grant, South Korea funded by the Ministry of Science, ICT, and Future Planning [NRF-2017R1C1B2004869, 2019R1A2B5B02070203, and 2018M3D1A1058744], South Korea.

Publisher Copyright:
© 2020 Elsevier B.V.


  • Electrocatalysts
  • Fe/Fe redox effect
  • Iron phosphates
  • Li–O battery
  • Thermal reaction

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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