The development of the scientific basics for the novel membrane materials manufacturing for electrochemical power units i.e. low temperature fuel cells (FC) efficiently working up to 300 °C is a serious scientific problem related to hydrogen energy shift. Polyantimonic acid (PAA) is characterized by high conductivity and thermal stability can be regarded as a prospective proton conducting material. So the goal of the current work was the investigation of the structure, phase stability, and protonic conductivity of PAA based solid electrolytes.