Hydration of the H⁺, Li⁺, Na⁺, and Cs⁺ ions in MF-4SK perfluorinated sulfonic acid cation-exchange membranes modified with inorganic dopants

• Published in: Russian journal of inorganic chemistry Vol. 56; no. 2; pp. 156 - 162
• Main Authors: Safronova, E. Yu, Volkov, V. I, Pavlov, A. A, Chernyak, A. V, Volkov, E. V, Yaroslavtsev, A. B
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : SP MAIK Nauka/Interperiodica 2011; SP MAIK Nauka/Interperiodica
• Subjects: Cations; Chemistry; Chemistry and Materials Science; Dopants; Humidity; Hydration; Inorganic Chemistry; Ion transport; Membranes; Silicon dioxide; Sulfonic acid; Synthesis and Properties of Inorganic Compounds; Sulfo Group; Zirconium Hydrogen; Phosphotungstic Acid; Inorganic Dopant; Alkali Metal Cation
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023611020240

The hydration, state, and mobility of protons and Li⁺, Na⁺, and Cs⁺ ions in MF-4SK perfluorinated sulfonic acid cation-exchange membranes doped with silicon dioxide and phosphotungstic acid have been investigated by NMR and impedance spectroscopy. The dopants increase the moisture content of the membrane and change the system of pores and channels in which ion transport takes place. At low humidities, the dopant particles are involved in ion transport. The greatest effect is observed for the membranes doped with both SiO₂ and phosphotungstic acid. The water molecules sorbed by dopant particles as a material participate in the hydration of alkali metal cations in the membrane.