Physico-Chemical Properties of NaV3O8 Prepared by Solid-State Reaction

Mariya Shchelkanova; Georgiy Shekhtman; Svetlana Pershina; Emma Vovkotrub

doi:10.3390/ma14226976

Physico-Chemical Properties of NaV₃O₈ Prepared by Solid-State Reaction

Materials (Basel). 2021 Nov 18;14(22):6976. doi: 10.3390/ma14226976.

Authors

Mariya Shchelkanova¹, Georgiy Shekhtman¹, Svetlana Pershina¹, Emma Vovkotrub¹

Affiliation

¹ Institute of High Temperature Electrochemistry, Ural Branch, Russian Academy of Sciences, 20 Akademicheskaya St., 620990 Ekatherinburg, Russia.

Abstract

Sodium-vanadium oxide NaV₃O₈ is synthesized via solid-state method and optimum synthesis conditions are chosen based on the data of DSC and TG analysis. The material synthesized is characterized by X-ray phase analysis, Raman spectroscopy and scanning electron microscopy. The ratio V⁴⁺/V⁵⁺ in the sample obtained is determined by X-ray photoelectron spectroscopy. Conductivity of the material synthesized was measured by impedance spectroscopy, pulse potentiometry and DC method over the range RT-570 °C. It is shown that NaV₃O₈ has rather high conductivity essentially electron in type (6.3 × 10^-2 at room temperature). AC and DC conductivity measurements are performed and cycling of symmetricNaV₃O₈|Na_3.85Zr_1.85Nb_0.15Si₃O₁₂|NaV₃O₈ cell in galvanostatic conditions. Thermal stability is studied across 25-570 °C temperature range. The results obtained are compared with the properties of NaV₃O₈ produced via aqueous solution.

Keywords: cathode materials; sodium power sources; sodium–vanadium oxides; solid state synthesis.