Synthesis, Characterization and Electrochemical Properties of Iron Doped Phosphate Tungsten Heteropoly Acid (Fe-PWA) and it’s Bronze (Fe-PWB): Comparative Study

Authors

  • Jovana Acković University of Priština in Kosovska Mitrovica, Faculty of Sciences and Mathematics, Department of Chemistry, 38220 Kosovska Mitrovica, Serbia
  • Ruzica Micić University of Priština in Kosovska Mitrovica, Faculty of Sciences and Mathematics, Department of Chemistry, 38220 Kosovska Mitrovica, Serbia
  • Zoran Nedić Faculty of Physical Chemistry, University of Belgrade, 11000 Belgrade, Serbia
  • Tamara Petrović Faculty of Physical Chemistry, University of Belgrade, 11000 Belgrade, Serbia
  • Jelena Senćanski Institute for General and Physical Chemistry, University of Belgrade, 11000 Belgrade, Serbia
  • Maja Pagnacco University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, 11000 Belgrade, Serbia
  • Pavle Tančić University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, 11000 Belgrade, Serbia

Abstract

In this work, synthesized 12-tungstenphosphoric acid (H3PW12O40 × nH2O; PWA) was further ionically exchanged with Fe3+ ions, which led to the formation of the 12-tungstophosporic acid iron salt, (FePW12O40 × nH2O; Fe-PWA). Fe-PWA was then subjected to thermal analysis (TGA/DTA), determining the phase transition temperature of 576°C from Fe-PWA to its corresponding phosphate tungsten bronze doped with iron, Fe-PWB. Using the X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR), and Scanning electron microscopy with an energy dispersive X-ray spectroscopy (SEM-EDS) method, the obtained Fe-PWA and Fe-PWB were additionally characterized, and compared. Due to channels and cavities in their structures, Fe-PWA and Fe-PWB were next examined as electrode materials for aqueous rechargeable batteries. Electrochemical measurements were done in aqueous solutions of 6 M LiNO3 by cyclic voltammetry. Fe-PWA and Fe-PWB exhibit different redox processes, which are discussed thoroughly in this work. Electrochemical results are showing that within the Fe-PWA structure, more Li+ ions can be intercalated in the first discharge cycle, but consecutive cycling leads to a fast capacity fade. While the Fe-PWB redox process was stable during cycling, its specific capacity is limited by the material's poor electrical conductivity. Improvements in Fe-PWB conductivity must be addressed in future studies in order to boost material’s electrochemical performance.

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Published

2024-08-12

Issue

Vol. 56 No. 3 (2024)

Section

Articles

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