Features of proton transport in composite electrolytes based on acid ammonium salt of 12-phosphotungstic acid and calixarene

• Published in: Solid state ionics 2022-04, Vol.377, p.115887, Article 115887
• Main Authors: Shmygleva, L.V., Leonova, L.S., Kayumov, R.R., Shilov, G.V.
• Format: Article
• Language: English
• Subjects: Acid ammonium salt; Calixarene; Calixarenes; Chemicals; Conductivity; Electrolytes; Heteropoly compound; Moisture content; Molten salt electrolytes; Phase transitions; Phosphotungstic acid; Proton conductivity; Protons; Solid composite electrolyte; Solid electrolytes; Spectrum analysis; Sulfonic acid
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2022.115887

The physicochemical properties of composite solid electrolytes based on acid ammonium salt of 12-phosphotungstic acid and calixarene sulfonic acid with uniform distribution were investigated. The proton conductivity was determined by the content and conductivity of calixarene and has the form of a saturation curve with reaching its maximum (0.1 S/cm at 20 °C and 75% RH) at a mole fraction of calixarene of 0.4. It was found that the water content and the activation energy of conduction nonmonotonically depend on the calixarene content with an extremum at the same calixarene content of ~0.4 (0.13 eV at 75% RH). The samples with a composition close to optimal do not experience phase transitions in wide range of temperature (from +60 to −60 °C). The observed behavior was explained on the basis of the results obtained with the help of differential scanning calorimetry, gravimetry, X-ray diffraction, scanning electron microscopy and impedance spectroscopy. •Impregnation allows obtaining electrolytes with a uniform distribution of components.•Addition of calixarene to the salt improves conductive properties of composites.•Proton conductivity is determined by the salt–calixarene boundary effects.•There is an optimal electrolyte composition.