Na-Ion Aqueous Batteries for Stationary Energy Storage Systems

The worrying increase in the emission of contaminants to the atmosphere and the depletion of the fossil fuels’ reserves are motivating the development of renewable energies and large-scale rechargeable energy storage devices. Current technologies used in grid storage include Na-S, Li-ion, Lead-acid and Nickel-Cadmium. With a clear predominance of sodium-based systems which have been implanted as an alternative to Li-ion since they are potentially less expensive and more environmentally friendly (sodium is more abundant, evenly spread and easier to extract than lithium) [1]. Nevertheless, the use of molten sodium and sulphur at 300-350 ºC present safety hazards and now research is being directed towards room temperature systems, such as Na-ion and Na-O₂ batteries [1]. Within this context, Na-ion aqueous batteries hold promise for stationary applications since, although the cell voltage is lower, they are safer than the above mentioned technologies and could represent a disruptively low cost system [1, 2]. Several electrode materials have been proposed for aqueous systems, such as manganese oxide [3], Na₂FeP₂O₇ [4] and Prussian blue analogues [5] for the positive side and NaTi₂(PO₄)₃ [6] as negative electrode.

During the presentation, we will show the results of our study [7] of low-cost Fe-based cathode materials for aqueous sodium-ion batteries: on one hand, polyanionic materials with higher capacity than Na₂FeP₂O₇, and on the other hand, Prussian-blue analogues which so far have demonstrated promising rate capabilities, round trip energy efficiencies and good cyclabilities [5]. The different materials have been tested in both organic and aqueous electrolyte at different rates and temperatures in order to evaluate their performances for possible applications in stationary storage. Ultimately, full cells using some of the possible anodes for this kind of systems will be also presented.

References

[1]           V. Palomares, M. Casas-Cabanas, E. Castillo-Martinez, M.H. Han, T. Rojo. Update on Na-based battery materials. A growing research path. Energy Environ. Science 6(2013) 2312–2337.

[2]           H. Kim,. J. Hong, K-Y. Park, H. Kim, S-W. Kim, Aqueous Rechargeable Li and Na ion batteries, Chem. Rev. DOI: 10.1021/cr500232.

[3]           J.F. Whitacre, T.Wiley, S.Shanbhag, Y.Wenzhuo, A.Mohamed, S.E. Chun, E.Weber, D.Blackwood, E.Lynch-Bell, J.Gulakowski, C.Smith, D.Humphreys, An aqueous electrolyte, sodium ion functional, large format energy storage device for stationary applications, J. Power Sources 213(2012) 255–264.

[4]           Y-H. Jung, C-H. Lim, J-H. Kim, D-K. Kim. Na₂FeP₂O₇ as a positive electrode material for rechargeable aqueous sodium-ion batteries. R. Soc. Chem. Adv., 4(2014) 9799–9802.

[5]           C.D. Wessells, S.V. Peddada, R.A. Huggins, Y.Cui, Nickel hexacyanoferrate nanoparticle electrodes for aqueous sodium and potassium ion batteries. Nano Lett. 11(2011):5421–5425

[6]           S. Park, I. Gocheva, S. Okada, J. Yamaki, Electrochemical properties of NaTi₂(PO₄)₃ anode for rechargeable aqueous sodium-ion batteries. J. Electrochem. Soc. 158(2011) 1067–1070.

[7]           A.J. Fernández-Ropero, D. Saurel, B. Acebedo, T.Rojo, M.Casas-Cabanas. Submitted.