Èlektrohimiâ

This review examines the literature, mainly of recent years, on the current topic of using graphenes in supercapacitors. The influence of the porous structure of graphenes, the influence of doping and irradiation of graphenes are considered. Methods for producing graphenes, composites of graphenes with metal oxides, sulfides and selenides, with metal particles, with electron-conducting polymers, with MXenes, as well as quantum dots are considered. Electrochemical characteristics are given for the types of graphene considered.

In this work, the thermal and electrical properties of the Y³⁺-doped Ba₇In_5.9Y_0.1Al₂O₁₉ phase, characterized by a hexagonal perovskite structure (a = 5.935(7) Å, c = 37.736(8) Å), were studied. It has been established that the phase is capable of incorporating protons and exhibiting proton conductivity. The introduction of an isovalent dopant, yttrium, led to an increase in the concentration of protons (up to the limiting values of Ba₇In_5.9Y_0.1Al₂O₁₉ ·0.55H₂O), as a result of an increase in the unit cell volume and, accordingly, the free space for the placement of OH^–-groups in an oxygen-deficient block containing coordination-unsaturated polyhedra [BaO₉]. Isovalent doping led to an increase in the oxygen-ion conductivity, which is due to an increase in interatomic distances and a decrease in the migration activation energy. In a humid atmosphere (pH₂O = = 1.92·10^–2 atm), the Ba₇In_5.9Y_0.1Al₂O₁₉ phase exhibited higher values of proton conductivity compared to the matrix compound Ba₇In₆Al₂O₁₉ and below 500°C it was characterized by dominant proton transport both in air and in a wide range of pO₂ (10^–18–0.21 atm).

Monophase powders of cubic modification with nominal composition Li_6.4Al_0.2La₃Zr₂O₁₂ (Al–LLZ) and Li_6.52Al_0.08La₃Zr_1.75Ta_0.25O₁₂ (Ta–LLZ) were synthesized. Dense (~97–98%) ceramic samples of solid electrolyte with increased stability in air were obtained from these powders by spark plasma sintering. High Li-ion conductivity (4–6×10^–4 S/cm) corresponding to the world level have been achieved.

The influence of addition of citric acid monohydrate on anodic dissolution and corrosion rate of aluminium in KOH solutions in 90% ethanol containing additives of gallium and indium compounds has been considered. It is shown that the introduction of citric acid monohydrate into the solution allows to reduce the magnitude of aluminium corrosion current without reducing the rate of its anodic dissolution. The inhibition efficiency of citric acid monohydrate when introduced into the solution at a concentration of 5∙10^–4 M is 58%. The discharge galvanostatic curves in the above electrolyte show a flat discharge plateau up to a discharge current density of 16 mA/cm².