M. E. Kompan

Nanocomposites with Mixed Electronic and Protonic Conduction for Electrocatalysis

Novel multipurpose electrode materials that have various catalytic applications are developed. The materials are composites based on multiwalled carbon nanotubes and electroconducting polymer polyaniline, organized as “fiber in a jacket.” Nanoparticles of metallic platinum and compounds of transition metals are additionally immobilized in the polymer layer. It is demonstrated experimentally that the materials possess high electronic and protonic conductance, thermal stability, hydrophilicity, large specific surface area, and considerable porosity.

Properties of proton-conducting Nafion-type membranes with Nanometer-thick polyaniline surface layers

The study is directed to the improving of proton-conducting Nafion-type membranes for using in fuel cells with direct oxidation of liquid fuels. Nanometer-thick layer of polyaniline (in its conducting emerald-dine form) was deposited onto the membrane surface by in situ polymerization. The structure of the polyaniline layer is studied, as well as the properties of thus modified membranes (electronic and proton conduction, permeability for methanol, thermal stability). A method of platinum catalyst deposition onto the Nafion-modifying polyaniline layer is developed.

Thermal conductivity of a composite medium with a disperse graphene filler

The possibility of decreasing the effective heat-transfer coefficient of insulating materials due to the introduction of small amounts of graphene-like clusters is considered. It is shown that the effect of screening thermal radiation by introduced clusters at their low concentration significantly exceeds the effect of increasing the thermal conductivity

Specific features of hydrogenation of chromium-doped polycrystalline thin vanadium dioxide films

It has been found that hydrogen penetration into chromium-doped polycrystalline thin vanadium dioxide films occurs with a lower rate than in the case of pure vanadium dioxide films. It has been shown that hydrogenation of films with low chromium concentrations is accompanied by a decrease in the phase transition temperature below Tc = 340 K. However, at room temperature in these hydrogenated films, no traces of M1 monoclinic phase have been observed. As the chromium concentration increases, hydrogenation ceases to be accompanied by the decrease in the phase transition temperature.

Ultimate capacitance characteristics of graphene electrodes for supercapacitors: Quantum restrictions

Factors influencing the specific parameters of porous carbon electrodes for supercapacitors are considered. Specific capacitance and charge characteristics of a graphene-based electrode material are calculated based on the density of states. The maximum possible specific capacitance of nanostructured electrode materials is determined.

Polymer–carbonaceous composites as electrode materials with high electrochemical capacitance

Using the aniline oxidative polymerization, polyaniline–carbonaceous material composites were synthesized, in which polymer layer at the carbon particle surface forms fibers oriented perpendicularly to the support surface. Conductivity, surface properties, and electrochemical activity of the composites in wide composition range are studied. The composites with fibrous morphology of polymer layer are shown to have much higher electrochemical capacitance than those with dense and homogeneous polyaniline layer.

Capacitance characteristics of nanoporous carbon materials in ionistors based on RbAg4I5 solid electrolyte

Characteristics of solid-state ionistors developed on the basis of nanoporous carbon synthesized by chlorination of metal carbides are presented. It is shown that the energy storage density in this type of devices reaches 150 J/g when they are operated in the hybrid mode.

Inductive Component of Impedance of Supercapacitor Porous Interface

Inductive response of supercapacitor to switching of charging current has been examined. The observed effect has been interpreted as a consequence of mechanical inertia of liquid conducting system (electrolyte). The proposed interpretation has been confirmed by simulation experiment.

Electrically conductive polyaniline—A molecular magnet with the possibility of chemically controlling the magnetic properties

Different forms of an electrically conductive polymer, an organic semiconductor, namely, polyaniline, have been synthesized and characterized. The magnetization curves of the obtained forms have been analyzed. It has been found that, in the oxidized form, the material exhibits a magnetic hysteresis at room temperature. For polyaniline without a special doping with magnetic additives, this result has been obtained for the first time. The possibility of controlling the magnetic properties of the material by means of chemical treatment at the post-polymerization stage has been demonstrated.

Nonlinear impedance of solid-state energy-storage ionisters

Impedance of ionisters (solid-state energy-storage capacitors) is studied. The study is performed in the voltage region where there is no contribution of the Faraday capacitance at low alternating voltages. It is found that the dependence of the impedance hodograph on the magnitude of the alternating voltage is much stronger than that on the applied direct voltage. Interpretation of this effect is proposed that allows for the conduction mechanism of the superionic conductor in a porous carbon matrix. A diagnostic technique is proposed for estimating the prospects of application of particular porous materials in ionisters.