Synthesis and conductivity performance of K_0.57WO₃ tungsten bronze with gaseous permeating of K₇MnFeW₁₁O₃₉⋅13H₂O by Sm

Highlights: • MnFeW₁₁ with Keggin structure was synthesized for the first time. • K_0.57WO₃ tungsten bronze is the main production in the permeated sample. • The electrical conductivity increases by approximately 1000 times after permeation. • The present work provides a new method for solid electrolyte conducting materials. - Abstract: Heteropoly compound K₇MnFeW₁₁O₃₉⋅13H₂O(Abbr.:MnFeW₁₁) with Keggin structure was synthesized by the stepwise acidification and the stepwise addition of element solutions. A new method named Rare Earth Gas Phase-Heated Diffused Permeation was explored to synthesize K_0.57WO₃ tungsten bronze through permeating earth element Sm into heteropoly compound MnFeW₁₁ at 550 °C. MnFeW₁₁ and production of permeation were characterized by IR, XRD, ICP, XPS and TG-DTA. Conductivity of that was investigated by four-electrode method. The results of IR and XRD indicate that Keggin structure of heteropoly compound MnFeW₁₁ is changed by the permeation, the bond of W–O–W is broken, and the main production named K_0.57WO₃ tungsten bronze is formed with tungsten-oxygen octahedra solely linked by corners. ICP and XPS results show that Sm binds with components of permeation. Production of permeation has a high conductivity (4.17 × 10⁻⁴ S cm⁻¹), which is 1000 times higher than that of the original sample