Journal of Materials Science: Materials in Electronics

Nowadays, the application of supercapacitor in energy storage is more and more extensive, and the selection and preparation of electrode material have become a formidable challenge. Polyaniline (PANI) has turned into one of the most hopeful conductive polymers due to its superior properties. In this article, conductive polyaniline was synthesized by chemical oxidative polymerization to acquire excellent electrochemical properties. Scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry (CV), and galvanostatic charge–discharge (GCD) measurements were adopted to explore the microstructure and energy storage capacity. The PANI is in coralline network morphology with high surface area, which can supply more active sites during charge and discharge process. The PANI shows a high specific capacitance value of 790 F/g, and the highest conductivity is 15.5 S/cm. The consequence shows that PANI synthesized under certain conditions has a promising feasibility for applications in high-performance supercapacitor electrode material.

Carboxymethyl cellulose (CMC)/graphene nanoplatelet (GnP) nanocomposite films containing different volume fractions (0.00, 0.73, 1.46, 2.20, 2.94, and 3.68) were prepared by ultrasonication assisted solution casting method. The effect of GnPs on structural, electrical, optical properties, and dispersion parameters of the nanocomposite have been investigated by a fourier transform infrared (FTIR), scanning electron microscope (SEM), two-point probe resistivity measurement, UV–Vis absorbance, and reflectance spectroscopy. The direct (Ed) and indirect (Ei) optical band gap energies of nanocomposites were determined using Tauc and absorbance spectrum fitting (ASF) methods. The results demonstrated that the optical band gap energies could be adjusted by altering the GnP volume fraction. Additionally, it was found that the outcomes obtained through the Tauc and ASF methods were very close to each other. The electrical conductivity (σ), Urbach energy (Eu), refractive index (n), dispersion energy (Edo), optical conductivity (σopt), and optical dielectric constant (ε) of CMC/GnP nanocomposite were found to increase with increasing GnP volume fraction (V). The improvements in structural, electrical, optical, dispersion parameters, and optical dielectric properties of these nanocomposites make them a potential candidate for many industrial applications.

Nitrogen-doped graphene supported NiFe2O4 nanoparticles (NiFe2O4-NG) composite was successfully synthesized by a simple hydrothermal method. In the NiFe2O4-NG nanocomposite, the surface of nitrogen-doped graphene sheets was loaded by a large number of uniform NiFe2O4 nanoparticles with the mean size of 8 nm. Meanwhile, the nitrogen-doped graphene sheets were exfoliated. As anode materials for lithium ion batteries, the initial discharge and charging capacities of NiFe2O4-NG electrode are 1888 and 1242 mAh g−1, respectively, and the coulomb efficiency is 65.8%. Furthermore, the capacity of NiFe2O4-NG is 1100 mAh g−1 after 50 cycles. Compared with pure NiFe2O4, the superior electrochemical performance of the NiFe2O4-NG nanocomposite is mainly attributed to the unique architecture of smaller NiFe2O4 nanoparticles loaded on the high conductivity of nitrogen-doped graphene sheets, as well as the synergy effect between the nitrogen-doped graphene and nanoparticles. The high specific surface area of NiFe2O4-NG can increase the interface area between electrode and electrolyte, ensuring the full contact between electrode surface and electrolyte. The strong interaction between nitrogen-doped graphene and nanoparticle is beneficial to effectively suppress the volume expansion and the rapid ion/electron transport during the charge–discharge process. Profiting from structure and composition characteristics, the above-mentioned NiFe2O4-NG electrode delivers an excellent capacity, cycle performance and rate capability.

Two different nanoparticles with different weight percentages (where x = 0.0, 0.2, 0.4, 0.8, and 1.0 wt%) have been added to the superconducting system with the general formula Bi1,8Pb0,3Sr2Ca2Cu3Oy + x(A/B) (A = Y2O3 and B = Sb2O3). The samples have been prepared with solid state reaction method. The aim of the study was to investigate and compare the effects of nano-Sb2O3 and nano-Y2O3 addition on the superconductivity, structural, magnetic, and mechanical properties of the system. X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive spectroscopy (EDX), vibrating sample measurement (VSM), DC resistivity–temperature measurement, and Vickers microhardness measurement (VHM) have been made for samples structural characterizations. XRD analysis presented that samples have orthorhombic crystal structure and both Bi-2223 and Bi-2212 phases coexist in the samples. In SEM photographs, granular structure is plate-like and particles are randomly oriented. M–H measurements have been performed at T = 15 K. Using Bean model, critical current densities have been calculated. Calculated J(0) values are 396 kA/cm2 and 232 kA/cm2 for nano-Sb2O3 and nano-Y2O3, respectively. Nano-Sb2O3 additive has been created stronger artificial needling center and higher critical current density than nano-Y2O3. R–T results has showed that nano-Sb2O3 addition increased critical temperature value (range of 109.92 and 112.48 K ), while nano-Y2O3 addition decreased (range of 90.53 and 110.68 K). VHM results showed that nano-Y2O3 addition samples have bigger hardness values than nano-Sb2O3 addition samples. Both doping materials increased the mechanical hardness of the system.

(Ba1−xSrxTi0.6Zr0.3Mn0.1O3) x = 0.1 and 0.2 ferroelectric material were synthesized by solid state method. XRD studies confirmed the single phase formation, and the functional group confirmation was done using Fourier transform infrared spectroscopy. Dielectric relaxations were observed at different frequency ranges for different temperatures. Activation energy Ea is calculated using Arrhenius equation from impedance and modulus which corresponds to the existence of oxygen vacancies.

ZnS nanoparticles were successfully synthesized by reflux under an alkaline medium. The nanoparticles were characterized by using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optical properties of ZnS nanoparticles were examined by photoluminescence (PL) spectrum. The result shows that the as-synthesized ZnS nanoparticles had a cubic phase. SEM image shows that ZnS nanoparticles are basically in spherical shape and are homogeneous. The particle size was found to be in the range of 18 nm.

Growth of Sb2Se3 thin films via pulsed laser deposition technique using presynthesized ball-milled Sb2Se3 compound material as a source has been attempted in this work. Films were grown at room temperature and at a substrate temperature of 320 °C. The films grown at 320 °C showed a crystalline orientation along (020). Raman studies confirmed Sb2Se3 phase formation along with the presence of Sb2O3 for films grown at 320 °C that was followed by X-ray photoelectron spectroscopy analysis, which indicated the presence of oxide formation, wherein the identified valence states of Sb and Se confirmed the compositional stoichiometry. Optical transmittance studies yielding a bandgap of ~ 1.29 eV matched with reported values and the absorption values were of the order of ~ 106 cm−1 in the visible region. Scanning electron microscopy showed the morphology of Sb2Se3 grown at 320 °C having a surface devoid of cracks and the cross-section SEM showed the film having a thickness of ~ 1 µm. Energy-dispersive X-ray spectroscopy of films grown at 320 °C showed near stoichiometric compositional values with slight selenium deficiency. Resistivity was calculated using a two-point probe method that showed a value of ~ 6 × 108 Ω-cm for Sb2Se3 films grown at 320 °C. Hot point probe measurement showed the film to be a p-type semiconductor.