Unveiling the sodium intercalation properties in Na1.860.14Fe3(PO4)3

Rachid Essehli, Hamdi Yahia, Kenza Maher, M. T. Sougrati, Ali Abouimrane, J. B. Park, Y. K. Sun, M. A. Al-Maadeed, I. Belharouak

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The new compound Na1.860.14Fe3(PO4)3 was successfully synthesized via hydrothermal synthesis and its crystal structure was determined using powder X-ray diffraction data. Na1.86Fe3(PO4)3 was also characterized by operando XRD and Mössbauer spectroscopy, cyclic voltammetry, and galvanostatic cycling. Na1.86Fe3(PO4)3 crystallizes with the alluaudite-type structure with the eight coordinated Na1 and Na2 sodium atoms located within the channels. The combination of the Rietveld- and Mössbauer-analyses confirms that the sodium vacancies in the Na1 site are linked to a partial oxidation of Fe2+ during synthesis. The electrochemical tests indicated that Na1.86Fe3(PO4)3 is a 3 V sodium intercalating cathode. At the current densities of 5, 10, and 20 mA g−1, the material delivers the specific capacities of 109, 97, and 80 mA h g−1, respectively. After 100 charge and discharge cycles, Na1.86Fe3(PO4)3 exhibited good sodium removal and uptake behavior although no optimizations of particle size, morphology, and carbon coating were performed.

Original languageEnglish
Pages (from-to)657-664
Number of pages8
JournalJournal of Power Sources
Publication statusPublished - 30 Aug 2016



  • Intercalation
  • NaFe(PO)
  • Phosphate
  • Positive electrode
  • Sodium ion batteries

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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