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The unique structural evolution of the O3-Phase Na2/3Fe2/3Mn1/3O2 during high rate charge/discharge: a sodium-centred perspective

Journal Article


Abstract


  • The development of new insertion electrodes in sodium-ion batteries requires an in-depth understanding of the relationship between electrochemical performance and the structural evolution during cycling. To date in situ synchrotron X-ray and neutron diffraction methods appear to be the only probes of in situ electrode evolution at high rates, a critical condition for battery development. Here, the structural evolution of the recently synthesized O3-phase of Na2/3Fe2/3Mn1/3O2 is reported under relatively high current rates. The evolution of the phases, their lattice parameters, and phase fractions, and the sodium content in the crystal structure as a function of the charge/discharge process are shown. It is found that the O3-phase persists throughout the charge/discharge cycle but undergoes a series of two-phase and solid-solution transitions subtly modifying the sodium content and atomic positions but keeping the overall space-group symmetry (structural motif). In addition, for the first time, evidence of a structurally characterized region is shown that undergoes two-phase and solid-solution phase transitions simultaneously. The Mn/Fe-O bond lengths, c lattice parameter evolution, and the distance between the Mn/FeO6 layers are shown to concertedly change in a favorable manner for Na+ insertion/extraction. The exceptional electrochemical performance of this electrode can be related in part to the electrode maintaining the O3-phase throughout the charge/discharge process.

Authors


  •   Sharma, Neeraj (external author)
  •   Gonzalo, Elena (external author)
  •   Pramudita, James C. (external author)
  •   Han, Man Huon (external author)
  •   Brand, Helen (external author)
  •   Hart, Judith (external author)
  •   Pang, Wei Kong.
  •   Guo, Zaiping
  •   Rojo, Teófilo (external author)

Publication Date


  • 2015

Citation


  • Sharma, N., Gonzalo, E., Pramudita, J. C., Han, M., Brand, H. E.A., Hart, J. N., Pang, W. Kong., Guo, Z. & Rojo, T. (2015). The unique structural evolution of the O3-Phase Na2/3Fe2/3Mn1/3O2 during high rate charge/discharge: a sodium-centred perspective. Advanced Functional Materials, 25 (31), 4994-5005.

Scopus Eid


  • 2-s2.0-84939260164

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/4160

Has Global Citation Frequency


Number Of Pages


  • 11

Start Page


  • 4994

End Page


  • 5005

Volume


  • 25

Issue


  • 31

Place Of Publication


  • Germany

Abstract


  • The development of new insertion electrodes in sodium-ion batteries requires an in-depth understanding of the relationship between electrochemical performance and the structural evolution during cycling. To date in situ synchrotron X-ray and neutron diffraction methods appear to be the only probes of in situ electrode evolution at high rates, a critical condition for battery development. Here, the structural evolution of the recently synthesized O3-phase of Na2/3Fe2/3Mn1/3O2 is reported under relatively high current rates. The evolution of the phases, their lattice parameters, and phase fractions, and the sodium content in the crystal structure as a function of the charge/discharge process are shown. It is found that the O3-phase persists throughout the charge/discharge cycle but undergoes a series of two-phase and solid-solution transitions subtly modifying the sodium content and atomic positions but keeping the overall space-group symmetry (structural motif). In addition, for the first time, evidence of a structurally characterized region is shown that undergoes two-phase and solid-solution phase transitions simultaneously. The Mn/Fe-O bond lengths, c lattice parameter evolution, and the distance between the Mn/FeO6 layers are shown to concertedly change in a favorable manner for Na+ insertion/extraction. The exceptional electrochemical performance of this electrode can be related in part to the electrode maintaining the O3-phase throughout the charge/discharge process.

Authors


  •   Sharma, Neeraj (external author)
  •   Gonzalo, Elena (external author)
  •   Pramudita, James C. (external author)
  •   Han, Man Huon (external author)
  •   Brand, Helen (external author)
  •   Hart, Judith (external author)
  •   Pang, Wei Kong.
  •   Guo, Zaiping
  •   Rojo, Teófilo (external author)

Publication Date


  • 2015

Citation


  • Sharma, N., Gonzalo, E., Pramudita, J. C., Han, M., Brand, H. E.A., Hart, J. N., Pang, W. Kong., Guo, Z. & Rojo, T. (2015). The unique structural evolution of the O3-Phase Na2/3Fe2/3Mn1/3O2 during high rate charge/discharge: a sodium-centred perspective. Advanced Functional Materials, 25 (31), 4994-5005.

Scopus Eid


  • 2-s2.0-84939260164

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/4160

Has Global Citation Frequency


Number Of Pages


  • 11

Start Page


  • 4994

End Page


  • 5005

Volume


  • 25

Issue


  • 31

Place Of Publication


  • Germany