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On Improvements of Sodium Manganese Oxide Materials as Sodium-Ion Battery (NIB) Cathode

Wednesday (28.09.2016)
11:45 - 12:00
Part of:

Mainly due to potential cost advantages sodium-ion batteries (NIBs) have the potential to become an alternative to lithium-ion batteries. Layered sodium manganese oxide is a material class seen as suitable candidate for future NIB cathodes, owing to a good compromise between operating voltage and capacity, so as for the low cost and high abundance of manganese. However, cycling stability still remains a problem.[1,2]

The scope of this work was to investigate different approaches to address the low cycling stability of the base material of this structural class, i.e. P2-NaxMnO(2+z) (x ≈ 0.7, z = 0.05 – 0.25) and to identify levers for improvements. Two successful strategies are presented in this work. One approach is the incorporation of a relatively small amount of cobalt (~10%) into the host structure leading to significant performance improvement; the other is an optimisation of the morphology. A combination of both strategies leads to a material with comparably best discharge capacity and cycling stability.

The underlying mechanism were investigated in comparison studies by applying various techniques.[3–5] By utilising operando X-ray diffraction we were able to related Co-doping and morphology to structural changes and battery performance.[5] These results were correlated with electrochemical studies. Preliminary results employing X-ray absorption spectroscopy and high resolution X-ray spectro-microscopy to further understand how the chemical and structural changes occurring across the entire electrode and spatially resolved within individual hollow spheres impact cycling performance are in preparation.

[1] M. H. Han, E. Gonzalo, G. Singh and T. Rojo, Energy Environ. Sci., 2015, 8, 81–102.

[2] K. Kubota, N. Yabuuchi, H. Yoshida, M. Dahbi and S. Komaba, MRS Bull., 2014, 39, 416–422.

[3] N. Bucher, S. Hartung, I. Gocheva, Y. L. Cheah, M. Srinivasan and H. E. Hoster, J. Solid State Electrochem., 2013, 17, 1923–1929.

[4] N. Bucher, S. Hartung, A. Nagasubramanian, Y. L. Cheah, H. E. Hoster and S. Madhavi, ACS Appl. Mater. Interfaces, 2014, 6, 8059–8065.

[5] N. Bucher, S. Hartung, J. B. Franklin, A. M. Wise, L. Y. Lim, H.-Y. Chen, J. N. Weker, M. F. Toney and S. Madhavi, Chem. Mater., 2016, 28, 2041–2051.


Additional Authors:
  • Dr. Steffen Hartung
  • Dr. Joseph B. Franklin
    Nanyang Technological University
  • Dr. Anna M. Wise
    SLAC National Accelerator Laboratory
  • Dr. Linda Y. Lim
    SLAC National Accelerator Laboratory
  • Han-Yi Chen
  • Dr. Johanna Nelson Weker
    SLAC National Accelerator Laboratory
  • Dr. Michael F. Toney
    SLAC National Accelerator Laboratory
  • Prof. Madhavi Srinivasan
    Nanyang Technological University