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Interplay between electrochemistry and phase evolution of the P2-type Nax(Fe1/2Mn1/2)O2 cathode for use in sodium-ion batteries

Journal Article


Abstract


  • Sodium-ion batteries are the next-generation in

    battery technology; however, their commercial development is

    hampered by electrode performance. The P2-type

    Na2/3(Fe1/2Mn1/2)O2 with a hexagonal structure and P63/mmc

    space group is considered a candidate sodium-ion battery

    cathode material due to its high capacity (∼190 mAh·g−1) and

    energy density (∼520 mWh·g−1), which are comparable to

    those of the commercial LiFePO4 and LiMn2O4 lithium-ion

    battery cathodes, with previously unexplained poor cycling

    performance being the major barrier to its commercial

    application. We use operando synchrotron X-ray powder

    diffraction to understand the origins of the capacity fade of

    the Na2/3(Fe1/2Mn1/2)O2 material during cycling over the

    relatively wide 1.5−4.2 V (vs Na) window. We found a complex phase-evolution, involving transitions from P63/mmc (P2-type at

    the open-circuit voltage) to P63 (OP4-type when fully charged) to P63/mmc (P2-type at 3.4−2.0 V) to Cmcm (P2-type at 2.0−

    1.5 V) symmetry structures during the desodiation and sodiation of the Na2/3(Fe1/2Mn1/2)O2 cathode. The associated large cellvolume

    changes with the multiple two-phase reactions are likely to be responsible for the poor cycling performance, clearly

    suggesting a 2.0−4.0 V window of operation as a strategy to improve cycling performance. We demonstrated here that the P2-

    type Na2/3(Fe1/2Mn1/2)O2 cathode is able to deliver ∼25% better cycling performance with the strategic operation window. This

    significant improvement in cycling performance implies that by characterizing the phase evolution and reaction mechanisms

    during battery function we are able to propose these modifications to the conditions of battery use that improve performance,

    highlighting the importance of the interplay between structure and electrochemistry.

Authors


  •   Pang, Wei Kong.
  •   Kalluri, Sujith (external author)
  •   Peterson, Vanessa K. (external author)
  •   Sharma, Neeraj (external author)
  •   Kimpton, Justin A. (external author)
  •   Johannessen, Bernt (external author)
  •   Liu, Hua K.
  •   Dou, Shi Xue
  •   Guo, Zaiping

Publication Date


  • 2015

Citation


  • Pang, W. Kong., Kalluri, S., Peterson, V. K., Sharma, N., Kimpton, J., Johannessen, B., Liu, H. Kun., Dou, S. Xue. & Guo, Z. (2015). Interplay between electrochemistry and phase evolution of the P2-type Nax(Fe1/2Mn1/2)O2 cathode for use in sodium-ion batteries. Chemistry of Materials, 27 (8), 3150-3158.

Scopus Eid


  • 2-s2.0-84928664903

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/3983

Has Global Citation Frequency


Number Of Pages


  • 8

Start Page


  • 3150

End Page


  • 3158

Volume


  • 27

Issue


  • 8

Place Of Publication


  • United States

Abstract


  • Sodium-ion batteries are the next-generation in

    battery technology; however, their commercial development is

    hampered by electrode performance. The P2-type

    Na2/3(Fe1/2Mn1/2)O2 with a hexagonal structure and P63/mmc

    space group is considered a candidate sodium-ion battery

    cathode material due to its high capacity (∼190 mAh·g−1) and

    energy density (∼520 mWh·g−1), which are comparable to

    those of the commercial LiFePO4 and LiMn2O4 lithium-ion

    battery cathodes, with previously unexplained poor cycling

    performance being the major barrier to its commercial

    application. We use operando synchrotron X-ray powder

    diffraction to understand the origins of the capacity fade of

    the Na2/3(Fe1/2Mn1/2)O2 material during cycling over the

    relatively wide 1.5−4.2 V (vs Na) window. We found a complex phase-evolution, involving transitions from P63/mmc (P2-type at

    the open-circuit voltage) to P63 (OP4-type when fully charged) to P63/mmc (P2-type at 3.4−2.0 V) to Cmcm (P2-type at 2.0−

    1.5 V) symmetry structures during the desodiation and sodiation of the Na2/3(Fe1/2Mn1/2)O2 cathode. The associated large cellvolume

    changes with the multiple two-phase reactions are likely to be responsible for the poor cycling performance, clearly

    suggesting a 2.0−4.0 V window of operation as a strategy to improve cycling performance. We demonstrated here that the P2-

    type Na2/3(Fe1/2Mn1/2)O2 cathode is able to deliver ∼25% better cycling performance with the strategic operation window. This

    significant improvement in cycling performance implies that by characterizing the phase evolution and reaction mechanisms

    during battery function we are able to propose these modifications to the conditions of battery use that improve performance,

    highlighting the importance of the interplay between structure and electrochemistry.

Authors


  •   Pang, Wei Kong.
  •   Kalluri, Sujith (external author)
  •   Peterson, Vanessa K. (external author)
  •   Sharma, Neeraj (external author)
  •   Kimpton, Justin A. (external author)
  •   Johannessen, Bernt (external author)
  •   Liu, Hua K.
  •   Dou, Shi Xue
  •   Guo, Zaiping

Publication Date


  • 2015

Citation


  • Pang, W. Kong., Kalluri, S., Peterson, V. K., Sharma, N., Kimpton, J., Johannessen, B., Liu, H. Kun., Dou, S. Xue. & Guo, Z. (2015). Interplay between electrochemistry and phase evolution of the P2-type Nax(Fe1/2Mn1/2)O2 cathode for use in sodium-ion batteries. Chemistry of Materials, 27 (8), 3150-3158.

Scopus Eid


  • 2-s2.0-84928664903

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/3983

Has Global Citation Frequency


Number Of Pages


  • 8

Start Page


  • 3150

End Page


  • 3158

Volume


  • 27

Issue


  • 8

Place Of Publication


  • United States