Vibrational and impedance analysis of the β-stannic acid samples plasticized by perchloric acid

The β-stannic acid powders(I) containing various amounts of perchloric acid with an initial concentration of 56.2 wt% HClO₄ were studied by IR and Raman spectroscopy combined with XRD analysis and impedance spectroscopy. The addition of aqueous perchloric acid to I at room temperature leads to the adsorption compound formation. The degree of ionization of HClO₄ is 100%. Based on these studies, a structural model has been proposed, according to which the hydrated H⁺ and ClO₄ ^¯ ions fill the pores/capillaries of I. The structure of I does not change during the adsorption process of ions. The finely dispersed powder of I turns into a viscous transparent gel with an optimal ratio of reagents, which indicates its plasticization. The electrochemical properties of the plasticized samples were investigated by impedance method. It was found that plasticization can increase the proton conductivity by more than two orders of magnitude. The plasticized samples have sensory properties. The plot of conductivity $$ ₂₅ versus weight fractions of perchloric acid solution W reveals a linear dependence at RH = 32% and t = 25 °C in a wide range of W values. The maximum value of $$ ₂₅ = 0.43 S cm^-1 is achieved at W = 0.61. The straight line has a break at the very beginning due to the perchloric acid flow threshold.