Artem G. Glukharev

DLP and DIW were successfully employed for 3D printing of stable and active C ₃ N ₄ -based structures subsequently tested for their photo- and piezoelectric properties as well as electrochemical sensing.

The development of novel proton-conducting membrane materials for electrochemical power units, i.e., low temperature fuel cells (FCs), efficiently working up to 300 °C, is a critical problem related to the rapid shift to hydrogen energy. Polyantimonic acid (PAA) is characterized by high conductivity, sufficient thermal stability and can be regarded as a prospective proton-conducting material. However, the fabrication of bulk PAA-based membranes with high proton conductivity remains a challenging task. In the present work, for the first time, the authors report the investigation on proton conductivity of bulk PAA-based membranes in the temperature range 25–250 °C, both in dry air and in moisturized air. Using PAA powder and fluoroplastic as a binder, fully dense cylindrical membranes were formed by cold uniaxial pressing. The structures of the PAA-based membranes were investigated by SEM, EDX, XRD and Raman techniques. STA coupled with in situ thermo-XRD analysis revealed that the obtained membranes corresponded with Sb₂O₅·3H₂O with pyrochlore structure, and that no phase transitions took place up to 330 °C. PAA-based membranes possess a high-grain component of conductivity, 5 × 10⁻² S/cm. Grain boundary conductivities of 90PAA and 80PAA membranes increase with relative humidity content and their values change non-linearly in the range 25–250 °C.

The paper summarizes current data on ceramic zirconia-graphene composites. Basic types of graphene-containing additives and the main approaches for composite synthesis are considered. The effect of the additive type and synthesis procedure on the composite structure, mechanical (microhardness and crack resistivity) and electrical (conductivity at room and at elevated temperature) properties of the material is discussed.