The current research examines the impact of Ca²⁺ substitution on the phase and electrical properties of (Ba_1−xCa_x)Ti₄O₉, (x = 0.0, 0.3, 0.6, and 0.9) sintered pellets synthesized by solid-state reaction method. The as-synthesized samples were analyzed using X-ray diffraction (XRD) and impedance spectroscopy. The emergence of orthorhombic phase fit into space group Pnmm was revealed by XRD, and the addition of Ca resulted in a considerable shift in grain size. Dielectric properties were determined using an impedance spectroscopy in a wide frequency range from 1MHz to 3 GHz. The dielectric properties i.e., dielectric constant (ε_r) and dielectric loss ($tan\sigma$), were measured at 3 GHz frequency. The frequency-dependent parameters such as conductivity, dielectric constant, and dielectric loss indicated that the relaxation process is a Maxwell–Wagner type of interfacial polarization. The improved dielectric properties and low energy loss have made (Ba_1−xCa_x)Ti₄O₉ a prominent energy storage material. This study provides the possibility to improve its dielectric properties and reduce energy loss, making it an excellent energy storage material.

Cerium (Ce)-doped Ni_0.5Cd_0.5Ce_xFe_2−xO₄ (0.0 ≤ x ≤ 0.20) was synthesized using the sol–gel auto-combustion method. X-ray diffraction (XRD) analysis revealed that all the samples retained spinel cubic crystal structure with space group Fd3m at 800 °C. Crystal structure parameters, such as lattice constant, average crystallite size, and X-ray density were estimated from the major XRD (311) peak. Bulk density and porosity were also calculated. The average crystallite size was estimated to be in the range of 20–24 nm. SEM images displayed agglomerated particles with a porous morphology. The dielectric constant (${\epsilon }^{\prime }$) increased and the dielectric loss tangent (tan$\mathsf{\delta }$) decreased with rising Ce concentration. The hysteresis loop (M–H loop) was measured at room temperature using a vibrating-sample magnetometer (VSM), which showed a nonlinear decrease in magnetization and coercivity with increasing Ce concentration.

Flexible PVC/BT (Polyvinyl chloride/Barium Titanate) composite thick films with (0–30%) volume fractions of BaTiO₃ were fabricated via the solution casting method. The effects of BaTiO₃ filler on the phase, microstructure and dielectric properties of composite films were investigated. The XRD results revealed that BT particles are embedded in the PVC matrix with no chemical reaction taking place between the two phases. It was observed that the glass transition temperature of PVC had increased with the addition of BT. The frequency dispersion in the dielectric constant versus temperature curves indicated the relaxor nature of the composites. The dielectric constant (ε_r) measured at 40 °C, increased from 7.6 for pure PVC to 16.1 for 30% of BaTiO₃ content in PVC polymer matrix. It is suggested that BaTiO₃ ceramic powder enhanced the dielectric properties of PVC and may be used as a flexible dielectric material.

Tin oxide (SnO₂) and tin-based composites along with carbon have attracted significant interest as negative electrodes for lithium-ion batteries (LIBs). However, tin-based composite electrodes have some critical drawbacks, such as high volume expansion, low capacity at high current density due to low ionic conductivity, and poor cycle stability. Moreover, complex preparation methods and high-cost carbon coating procedures are considered main challenges in the commercialization of tin-based electrodes for LIBs. In this study, we prepared a Sn/SnO₂/C nano-composite structure by employing a low-cost hydrothermal method, where Sn nanoparticles were oxidized in glucose and carboxymethyl cellulose CMC was introduced into the solution. Scanning electron microscope (SEM) and transmission electron microscope revealed the irregular structure of Sn nanoparticles and SnO₂ phases in the conductive carbon matrix. The as-prepared Sn/SnO₂/C nano-composite showed high first-cycle reversible discharge capacity (2248 mAhg⁻¹) at 100 mAg⁻¹ with a first coulombic efficiency of 70%, and also displayed 474.64 mAhg⁻¹ at the relatively high current density of about 500 mAg⁻¹ after 100 cycles. A low-cost Sn/SnO₂/C nano-composite with significant electrochemical performance could be the next generation of high-performance negative electrodes for LIBs.

In the present work, pure and Cr-doped MoO₃ microrods were successfully prepared through the sol gel auto combustion method. The phase evaluation and microstructural, dielectric, and optical properties of synthesized samples were investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and an impedance analyzer (1 MHz–3 GHz). All the samples showed hexagonal structure with space group (P63). According to Vegard’s law, lattice parameters increase with the increase in chromium (Cr³⁺) contents. In addition, the Williamson–Hall (W–H) plot was drawn for evaluating the micro-strain (ε_W-H) and crystallite size (D_W-H) parameters. From microstructural analysis it was found that the size of microrods increased along with Cr³⁺ contents. Decreasing band gap energy was observed (from 2.98 to 2.71 eV) with increasing Cr³⁺ contents. The variation of the dielectric constant and tangent loss of MoO₃ microrods with respect to frequency were analyzed.

Transition metal dichalcogenides (TMDs), such as rhenium diselenide, have currently attracted a lot of attention as one of the novel candidates of the TMD family. However, sample fabrication remains a significant problem due to poor electrochemical performance, and synthesizing ReSe₂ with outstanding tailored features to encounter the high-level demands of noble metal replacement persists a challenge. As a result, we suggest a method for the production of ReSe₂ with controllable morphologies by simply changing the Re : Se ratio of the precursors. Herein, two distinct morphologies i.e. nanoparticles and nanobelts of ReSe₂ were synthesized using a hot injection approach. Phase study and modes of vibrations of both samples were investigated using X-ray diffraction crystallography (XRD) and Raman spectroscopy. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed ReSe₂ nanoparticle and nanobelt morphologies. The nanobelts ReSe₂ outperformed by achieving a current density of 10 mA cm⁻² at an over-potential of 96 mV whereas ReSe₂ nanoparticles attained a current density of 10 mA cm⁻² at 174 mV. The remarkable electrocatalytic performance of ReSe₂ nanobelts is due to their unique morphology, which allows for quick charge transfer kinetics and incredible stability even after 1000 CV cycles.