Synthesis, characterization and electrochemical properties of iron doped phosphate tungsten heteropoly acid (Fe-PWA) and it’s bronze (Fe-PWB): Comparative study

Autor: Acković Jovana, Micić Ružica, Nedić Zoran, Petrović Tamara, Senćanski Jelena, Pagnacco Maja, Tančić Pavle
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Science of Sintering, Vol 56, Iss 3, Pp 367-380 (2024)
Druh dokumentu: article
ISSN: 0350-820X
1820-7413
DOI: 10.2298/SOS230812053A
Popis: 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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