Search

In the work, nanostructured Fe3O4/C composites based on natural raw materials (beet pulp and corn stalks) are synthesised in various ways. Iron chloride FeCl3 is used as an activator. The synthesised composites are investigated using the following methods, scanning electron microscopy, X-ray diffractometry, nitrogen adsorption/desorption porometry, magnetometry, impedance and galvanostatic measurements. The presence of nanosized Fe3O4 magnetite in the synthesised carbon structures is disclosed. Based on the magnetic measurements, the particle size of Fe3O4 is on average 50 nm for the sample of the composite synthesised from beet pulp in one step, 30 nm for the sample of the composite synthesised from beet pulp in two steps, 33 nm for the composite synthesised from corn stalks in one step, and 29 nm for the composite synthesised from corn stalks in two steps. It is shown that the two-step synthesis using pre-carbonised raw materials gives the specific capacitance of the composite made with beet pulp at 96 F/g, and for the composite made with corn stalks at 95 F/g. The high coulombic efficiency (>95%) and the stability of the electrical capacitance during long-term cycling make it possible to use Fe3O4/C composites for the manufacture of supercapacitor electrodes with aqueous electrolytes. [ABSTRACT FROM AUTHOR]

In this work, we present findings on the syntheses and study of properties of InSe nanohybrid. The introduction of guest component in GaSe matrix leads to an increase in inhomogeneities, which is clearly confirmed by the strengthening of the low-frequency horizontal branch of Nyquist diagrams. A constant magnetic field counteracts this effect and changes the behavior of the impedance hodograph at low frequencies to the opposite. Illumination leads to a colossal increase in quantum capacitance, which is clearly demonstrated in the Nyquist diagram. For the synthesized InSe nanohybrid the interesting behavior of the current-voltage characteristic is reported. As a result of studies of the synthesized InSe nanohybrid the effect of "negative capacity" is observed, the magnitude of which can be controlled by the electric field. Based on the constructed impedance model and proposed N-barrier model, the physical mechanisms of the investigated processes are suggested. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)