Structural Stabilization of P2-type Sodium Iron Manganese Oxides by Electrochemically Inactive Mg Substitution: Insights of Redox Behavior and Voltage Decay

Junghoon Yang, Annalise E. Maughan, Glenn Teeter, Bertrand J. Tremolet de Villers, Seong Min Bak, Sang Don Han

Research output: Contribution to journalArticlepeer-review


Layered P2-type Na0.8Mn0.5Fe0.5O2 cathode material is a promising candidate for next-generation sodium-ion batteries due to the economical and environmentally benign characteristics of Mn and Fe. The poor cycling stability of the material, however, is still a problem that must be solved. To address the problem, electrochemically inactive Mg2+ was introduced into the structure by substituting some of the Fe ions. It was shown that Mg substitution led to a smoother voltage profile with improved cycling performance and rate capability. These observations were attributed to the suppressed structural changes during electrochemical processes. Detailed redox mechanisms, associated local structural changes, and phase transitions were investigated by X-ray absorption spectroscopy and X-ray diffraction. From the detailed analysis of electrochemical behaviors, it was also identified how the redox reactions and structural disordering occurred in the high- and low-voltage regions and how Mg substitution stabilized the structure.

Original languageEnglish
Pages (from-to)5972-5982
Number of pages11
Issue number22
Publication statusPublished - 2020 Nov 20

Bibliographical note

Funding Information:
This work was authored in part by Alliance for Sustainable Energy, LLC, the manager and operator of the National Renewable Energy Laboratory for the U.S. Department of Energy (DOE) under Contract No. DE‐AC36‐08GO28308. Funding for material synthesis, XRD, XPS, and electrochemical characterization provided by the Laboratory Directed Research and Development program. XAS support and analysis performed at Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the U.S. DOE through the Advanced Battery Materials Research (BMR) Program under Contract No. DE‐SC0012704. The XAS research used beamline 7‐BM (QAS) of the National Synchrotron Light Source II, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE‐SC0012704. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government.

Publisher Copyright:
© 2020 Wiley-VCH GmbH

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Chemical Engineering(all)
  • Materials Science(all)
  • Energy(all)


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