A Thermodynamic and Kinetic Study of Electrochemical Lithium Intercalation in Na0.33 V 2 O 5 Bronze Prepared by a Sol‐Gel Process

Abstract

Thermodynamic and kinetic investigations on the electrochemical lithium intercalation into synthesized by a sol‐gel process (SGP) have been found to correlate well with the scheme suggested for the filling of the available sites M of the β structure by Li⁺ ions. Indeed, the whole of the thermodynamic, kinetic, and crystallographic data have enabled one to explain the electrochemical behavior exhibited by the SGP bronze in a lithium ion containing non‐aqueous solvent. The partial molar quantities , , and were obtained from EMF‐temperature measurements and coulometric titration curves. Two main ordering processes were seen to take place in the composition range and in . The chemical diffusion coefficient of lithium was found to be proportional to the number of the vacant sites; varies from 10⁻⁹ up to 10⁻¹² cm² s⁻¹ for and is in the order 10⁻¹⁴ for higher Li contents. Finally, the better electrochemical behavior of the SGP bronze , as compared with that exhibited by the similar bronze obtained through solid‐state reactions at 700°C highlighted the advantage of the sol‐gel technique for the synthesis of new cathodic intercalation materials usable in secondary lithium cells.