Electrical Applications Research Articles

Study of the Effect of Graphene Content on the Electrical and Mechanical Properties of Aluminium–Graphene Composites

The present paper is dedicated to the search for an alternative material based on an aluminum (Al)—few-layer graphene (FLG) composite for use in electrical applications. Due to its excellent properties, graphene has the potential for use in many applications, especially in electronics, electrical engineering, aerospace, and the automotive industry. One area where the properties of graphene can be exploited is in overhead power transmission, where the main challenge at the moment is to reduce transmission losses. The utilization of conductors that exhibit superior electrical conductivity is instrumental in ensuring the mitigation of transmission losses. The utilization of graphene or other carbon allotropes is appealing due to their elevated electrical conductivity, substantial mechanical strength, and considerable heat resistance, which can enhance the properties of the composite, thereby increasing its resistance to operational conditions, particularly long-term exposure to temperature, a parameter closely related to the current carrying capacity of the OHL. This article presents the findings of research on the production of a composite based on aluminum powder and graphene, as well as the identification of its electrical and mechanical properties. The primary challenge in this research lies in the development of a method to synthesize carbon materials with aluminum using powder metallurgy, with particular attention paid to the mixing and compacting process, which is of significant importance in ensuring the appropriate distribution of carbon material in the composite. The research carried out has determined the influence of the graphene content (0.1–1 wt.%) on the electrical conductivity (max. 35.4 MS/m) and mechanical properties of Al-FLG composites (UTS = 156 MPa).

Cholesteric liquid crystal mixtures for the switchable smart windows and light shutters: electro-optical and dielectric behavior

Abstract Cholesteric liquid crystal (CLC) mixtures with variable pitch lengths were prepared for the electrical switchable smart window and light shutter applications by taking varied concentrations (2.6, 3.0, 4.0, and 5.0 wt%) of chiral dopant (R1011) having helical twisting power (HTP) 37.6 μm−1 and nematic E7 liquid crystal (LC). The morphological and electro-optical analysis of these CLC mixtures filled in 10µm thick cells were observed and reported herein, the switching of initial planar (P) and initial focal conic (FC) to homeotropic (H) states as well as vice-versa. The operating voltage of the 2.6 wt% of chiral doped CLC cell was relatively lower among all the sample cells compared with other concentrations. The maximum contrast ratio (CR) was observed for 5.0 wt% chiral doped CLC cell with initial planar state. However, the best CR was observed in 2.6wt% CLC cell with initial FC state. The comparative macroscopic views of the P, FC, and H states in the OFF and ON conditions of applied voltage for prepared CLC cells were observed for transparent and opaque states. Further, UV-visible spectroscopy was performed in the P, FC, and H states under the application of an externally applied field to observe the absorbance and band gap behavior of the fabricated CLC cells. Additionally, chiral concentration-dependent dielectric parameters with variable frequency in initial P and FC states of the fabricated cells were also reported. The temperature-dependent phase behavior of all the prepared cells exhibited a slight decrease in the isotropic phase of LC due to the doping of chiral dopants.

Study on the Influence of External Electric Field Control and Vibrational Quantum Effect on the Charge Separation Mechanism in Fullerene-Based Systems.

Based on the DCV-C60 system of fullerene acceptor organic solar cell active materials, the charge transfer process of D-A type molecular materials under the action of an external electric field (Fext) was explored. Within the range of electric field application, the excited state characteristics exhibit certain regular changes. Based on reducing the excitation energy, the excitation mode shows a trend of developing toward low excited states. The effect of solvent polarity on the stability and reorganization energy of the charge transfer state was investigated. The dependence of charge separation parameters on specific molecular structures within the electric field range was studied, proving that the electric field set along the electron transfer direction can indeed accelerate charge separation. The influence of vibrational modes on the charge separation process was studied, and the results showed that the vibrational quantum tunneling effect significantly promoted the charge separation. Therefore, considering the vibrational excitation effect and the perturbation of the nuclear-electron interaction is crucial for more accurate simulation of the electron-vibration coupling process in the excited state.

Six Sigma-Based Mathematical Optimization Framework for Flux-Switching Machines: A Roadmap for Quality, Performance, and Manufacturing Tolerances

Flux-switching wound field machines (FSWFMs) offer high torque density and independence from rare-earth materials, making them promising candidates for sustainable electric vehicles and industrial applications. However, their adoption is limited by challenges such as high torque ripple, efficiency variations, and sensitivity to manufacturing tolerances. This study presents a Design for Six Sigma (DFSS) optimization framework that integrates sensitivity analysis, response surface modeling (RSM), and multi-objective genetic algorithms to address these challenges. The optimized solution reduces torque ripple by 7.69%, improves torque output, and enhances energy efficiency. By incorporating Six Sigma principles, the framework ensures robust performance under manufacturing variations, bridging the gap between theoretical optimization and practical implementation. This scalable and efficient methodology establishes FSWFMs as viable solutions for industrial applications, revolutionizing electric machine design.

A Versatile Dual-Responsive Shape-Memory Gripper via Additive Manufacturing Toward High-Performance Cross-Scale Objects Maneuvering.

Smart grippers serving as soft robotics have garnered extensive attentions owing to their great potentials in medical, biomedical, and industrial fields. Though a diversity of grippers that account for manipulating the small objects (e.g., tiny micrometer-scale droplets) or the big ones (e.g., centimeter-scale screw) has been proposed, however, cross-scale maneuvering of these two species leveraging an all-in-one intelligent gripper is still challenging. Here, a magnet/light dual-responsive shape-memory gripper (DR-SMG) is reported, based on the hybrid of Fe-nanoparticles and shape-memory polymers. Thanks to its photothermal effect, the closed-state DR-SMG switches to the open state under the synergetic cooperation of near-infrared-ray (NIR) and a circinate magnetic field, referring to the temporary state. On the other hand, once the NIR is loaded, the temporary opened DR-SMG would reconfigure to its permanent closed state owing to shape-memory effect. Leveraging this principle, DR-SMG can grasp and release diverse cross-scale objects ranging from micrometers to centimeters including metals, glass balls, polymers, and small liquids. Significantly, this versatile DR-SMG is capable of spatially delivering multifunctional chemical droplets and conductive liquid metals, thereby enabling lab-on-chip and electrical switch applications. This work provides new insights into intelligent grippers and further advances the field of soft robotics.

Review of Thermal Management Techniques for Prismatic Li-Ion Batteries

This review presents a comprehensive analysis of battery thermal management systems (BTMSs) for prismatic lithium-ion cells, focusing on air and liquid cooling, heat pipes, phase change materials (PCMs), and hybrid solutions. Prismatic cells are increasingly favored in electric vehicles and energy storage applications due to their high energy content, efficient space utilization, and improved thermal management capabilities. We evaluate the effectiveness, advantages, and challenges of each thermal management technique, emphasizing their impact on performance, safety, and the lifespan of prismatic Li-ion batteries. The analysis reveals that while traditional air and liquid cooling methods remain widely used, 80% of the 21 real-world BTMS samples mentioned in this review employ liquid cooling. However, emerging technologies such as PCM and hybrid systems offer superior thermal regulation, particularly in high-power applications. However, both PCM and hybrid systems come with significant challenges; PCM systems are limited by their low thermal conductivity and material melting points. While hybrid systems face complexity, cost, and potential reliability concerns due to their multiple components nature. This review underscores the need for continued research into advanced BTMSs to optimize energy efficiency, safety, and longevity for prismatic cells in electric vehicle applications and beyond.

Study on the Influence of Nanofiller Additives in Enhancing Electrical Insulation Performance and Thermal Properties of Biodegradable Oils for Electrical Insulation Applications

Study on the Influence of Nanofiller Additives in Enhancing Electrical Insulation Performance and Thermal Properties of Biodegradable Oils for Electrical Insulation Applications

High-entropy engineered BaTiO3-based ceramic capacitors with greatly enhanced high-temperature energy storage performance

Ceramic capacitors with ultrahigh power density are crucial in modern electrical applications, especially under high-temperature conditions. However, the relatively low energy density limits their application scope and hinders device miniaturization and integration. In this work, we present a high-entropy BaTiO3-based relaxor ceramic with outstanding energy storage properties, achieving a substantial recoverable energy density of 10.9 J/cm3 and a superior energy efficiency of 93% at applied electric field of 720 kV/cm. Of particular importance is that the studied high-entropy composition exhibits excellent energy storage performance across a wide temperature range of −50 to 260 °C, with variation below 9%, additionally, it demonstrates great cycling reliability at 450 kV/cm and 200 °C up to 106 cycles. Electrical and in-situ structural characterizations revealed that the high-entropy engineered local structures are highly stable under varying temperature and electric fields, leading to superior energy storage performance. This study provides a good paradigm of the efficacy of the high-entropy engineering for developing high-performance dielectric capacitors.

Green Hydrogen for Energy Transition: A Critical Perspective

Green hydrogen (GH2) is emerging as a key driver of global energy transition, offering a sustainable pathway to decarbonize energy systems and achieve climate objectives. This review critically examines the state of GH2 research production technologies and their integration into renewable energy systems, supported by a bibliometric analysis of the recent literature. Produced via electrolysis powered by renewable energy, GH2 shows significant potential to decarbonize industries, enhance grid stability, and support the Power-to-X paradigm, which interlinks electricity, heating, transportation, and industrial applications. However, widespread adoption faces challenges, including high production costs, infrastructure constraints, and the need for robust regulatory frameworks. Addressing these barriers requires advancements in electrolyzer efficiency, scalable fuel cell technologies, and efficient storage solutions. Sector-coupled smart grids incorporating hydrogen demonstrate the potential to integrate GH2 into energy systems, enhancing renewable energy utilization and ensuring system reliability. Economic analyses predict that GH2 can achieve cost parity with fossil fuels by 2030 and will play a foundational role in low-carbon energy systems by 2050. Its ability to convert surplus renewable electricity into clean energy carriers positions it as a cornerstone for decarbonizing energy-intensive sectors, such as industry, transportation, and heating. This review underscores the transformative potential of GH2 in creating a sustainable energy future. By addressing technical, economic, and policy challenges and through coordinated efforts in innovation and infrastructure development, GH2 can accelerate the transition to carbon-neutral energy systems and contribute to achieving global climate goals.

Controlled Oxidation of Metallic Molybdenum Patterns via Joule Heating for Localized MoS2 Growth.

High-quality two-dimensional transition metal dichalcogenides (2D TMDs), such as molybdenum disulfide (MoS2), have significant potential for advanced electrical and optoelectronic applications. This study introduces a novel approach to control the localized growth of MoS2 through the selective oxidation of bulk molybdenum patterns using Joule heating, followed by sulfurization. By passing an electric current through molybdenum patterns under ambient conditions, localized heating induced the formation of a molybdenum oxide layer, primarily MoO2 and MoO3, depending on the applied power and heating duration. These oxides act as nucleation sites for the subsequent growth of MoS2. The properties of the grown MoS2 films were investigated using Raman spectroscopy and photoluminescence measurements, showing promising film quality. This study demonstrates that Joule heating can be an effective method for precise control over TMD growth, offering a scalable approach for producing high-quality 2D materials that have the potential to be integrated into next-generation electrical and optoelectronic technologies.

Advantages and Challenges of Graphene Transistors for High-Frequency Applications

Graphene is regarded as an ideal material for next-generation high-frequency (HF) electronic devices, attributed to its unique two-dimensional structure, high carrier mobility, and exceptional electrical properties. In recent years, the limitations of conventional silicon-based technologies for high-frequency applications have become increasingly apparent, resulting in heightened interest in graphene transistors, which exhibit significant potential for applications in wireless communications, radar systems, and terahertz technology. These transistors exhibit high cutoff frequency and low noise characteristics, along with favorable bipolar properties, which provide them with significant advantages in radio frequency (RF) applications. However, despite the significant theoretical advantages of graphene materials, their practical application is still restricted by multiple factors. Specifically, insufficient voltage gain from weak current saturation, material uniformity issues, and large-scale production challenges have restricted the widespread adoption of graphene transistors in high-frequency electronic devices. This paper reviews the relevant literature, examines the disparity between the electrical performance and practical applications of graphene transistors, and identifies the key factors influencing their implementation. The results demonstrate that targeted bandgap engineering, innovative device architectures, and the exploration of new materials can help graphene transistors can mitigate existing challenges and position themselves as key components in future HF electronic devices, driving significant advancements and broader integration of related technologies.

Photo-Rechargeable Sodium-Ion Batteries with a Two-Dimensional MoSe2 Crystal Cathode.

Combining energy harvesting with energy storage systems in a single device could offer great advantages for continuous power supply in both indoor and outdoor electric applications. In this work, we demonstrate a photochargeable sodium-ion battery (PSIB) based on a photoactive cathode of two-dimensional crystals of MoSe2. This photocathode enables spontaneous photodriven charging of a sodium-ion battery cathode under illumination and an increase in the reversible capacity to 29% at 600 mA g-1 compared to that under dark conditions during galvanostatic cycling. Exposure of MoSe2 to light drives the Na+ extraction, prompted by photogenerated holes, and accelerates the charge transfer kinetics with improved ion diffusion, which leads to an increased capacity. Moreover, the PSIB can be charged to 1.68 V under light illumination without applying an external current. Our work paves the way for the development of light-driven rechargeable batteries, which can benefit off-grid technologies such as the Internet of Things.

Critical Role of Rubber Functionalities on the Mechanical and Electrical Responses of Carbon Nanotube-Based Electroactive Rubber Composites.

Carbon nanomaterials, particularly carbon nanotubes (CNTs), are widely used as reinforcing fillers in rubber composites for advanced mechanical and electrical applications. However, the influence of rubber functionality and its interactions with CNTs remains underexplored. This study investigates electroactive elastomeric composites fabricated with CNTs in two common diene rubbers: natural rubber (NR) and acrylonitrile-butadiene rubber (NBR), each with distinct functionalities. For NR-based composites containing 2 vol% CNTs, mechanical properties, such as elastic modulus (2.24 MPa), tensile strength (12.48 MPa), and fracture toughness (26.92 MJ/m3), show significant improvements of 125%, 215%, and 164%, respectively, compared to unfilled rubber. Similarly, for NBR-based composites, the elastic modulus (5.46 MPa), tensile strength (13.47 MPa), and fracture toughness (82.89 MJ/m3) increase by 94%, 22%, and 65%, respectively, over the unfilled system. Although NBR-based composites exhibit higher mechanical properties, NR systems show more significant improvements, suggesting stronger chemical bonding between NR chains and CNTs, as evidenced by dynamic mechanical, X-ray diffraction, thermogravimetric, and thermodynamic analyses. The NBR-based composite at 1 vol% CNT content exhibits 261% higher piezoresistive strain sensitivity (GF = 65 at 0% ≤ Δε ≤ 200%) compared to the NR-based composite (GF = 18 at 0% ≤ Δε ≤ 200%). The highest gauge factor of 39,125 (1000% ≤ Δε ≤ 1220) was achieved in NBR-based composites with 1 vol% CNT content. However, 1.5 vol% CNT content in NBR provides better strain sensitivity and linearity than other composites. Additionally, NBR demonstrates superior electromechanical actuation properties, with 1317% higher actuation displacement and 276% higher electromechanical pressure compared to NR at an applied electric field of 12 kV. Due to the stronger chemical bonding between the rubber and CNT, NR-based composites are more suitable for dynamic mechanical applications. In contrast, NBR-based CNT composites are ideal for stretchable electromechanical sensors and actuators, owing to the high dielectric constant and polarizable functional groups in NBR.

Enhanced Optical and Dielectric Characteristics of PVC/PEG Blended Polymer via Loading ZnCo1.8Al0.2O4/LiTFSI/THAI for Emerging Optical and Electrical Applications

The current work aims to produce the PVC/PEG/ZnCo1.8Al0.2O4/LiTFSI/THAI blended polymers to employ in low-cost optoelectronics and energy storage applications. Poly(vinyl chloride) (PVC)/polyethylene glycol (PEG)/ZnCo1.8Al0.2O4/lithium bis(trifluoromethane)sulfonimide (LiTFSI)/x wt% tetrahexylammonium iodide (THAI) blended polymers were formed via a casting procedure. The doped blends containing THAI exhibit strong absorption across UVA, UVB, and UVC spectra. The minimum direct and indirect optical band gap values are (3.03, 3.83, 4.51)/(2.54, 3.18, 3.66) eV in the blend with 5 wt% THAI. At 550 nm, the refractive index increased to 1.702 upon doping the host blend with ZnCo1.8Al0.2O4/LiTFSI/3 wt% THAI. The effect of dopant on the optical dielectric constant, dielectric losses, Nyquist’ plots, and Argand plots’ was investigated. The doped fillers in the PVC/PEG blended polymer controlled the nonlinear optical parameter values. Bended polymer with 1 wt% THAI has greater quenching in the fluorescence intensity. A chromaticity diagram revealed that the blends have blue-violet-yellow colors based on the kind and ratio of the fillers. Blend with ZnCo1.8Al0.2O4/LiTFSI has the superior energy density value.

Selection criteria of polymer nanocomposites for electrical energy storage applications: A concise review

Selection criteria of polymer nanocomposites for electrical energy storage applications: A concise review

Dielectric Characteristics of Iridium Substituted Co0.05-xTi0.95O2 Dilute Magnetic Semiconductors for Electrical Device Applications

In the current study, a cost effective solid-state method have been used to prepare iridium (Ir) substituted and cobalt doped titanium dioxide (TiO2) dilute magnetic semiconductors (DMS) materials {i.e.; IrxCo0.05-xTi0.95O2; 0.00 ≤ x ≤ 0.05 DMS}. The impact of Ir substitution on structural, optical and dielectric properties for the prepared IrxCo0.05-xTi0.95O2; 0.00 ≤ x ≤ 0.05 DMS samples have been investigated using X-ray diffractometer, ultraviolet-visible spectroscopy and LCR (inductor, capacitor and resistor) meter, respectively. The structural analysis confirms the tetragonal rutile phase formation with space group p42/mnm-136, while the values of band gap energy increase with increasing Ir concentrations in prepared DMS materials and band gap value approaches the band gap energy of void band gap materials for large applications. The dielectric constant and tangent loss have been studied as a mapping of frequency (20Hz - 20MHz) at room temperature. Both the dielectric constant and tangent loss linearly decrease with increase in applied frequency and become stable at high frequency values, therefore, these DMS materials could be beneficial for storage and electrical device applications.

Virtual vector-based strategy with capacitor voltage balancing for three-level active neutral-point-clamped converters in electric propulsion applications

Virtual vector-based strategy with capacitor voltage balancing for three-level active neutral-point-clamped converters in electric propulsion applications

Giant anisotropic piezoresponse of layered ZrSe3.

We investigated the effect of uniaxial strain on the electrical properties of few-layer ZrSe3 devices under compressive and tensile strains applied up to ±0.62% along different crystal directions. We observed that the piezoresponse, the change in resistance upon application of strain, of ZrSe3 strongly depends on both the direction in which electrical transport occurs and the direction in which uniaxial strain is applied. Notably, a remarkably high anisotropy in the gauge factor for a device with the transport occurring along the b-axis of ZrSe3 with GF = 68 when the strain is applied along the b-axis was obtained, and GF = 4 was achieved when strain is applied along the a-axis. This leads to an anisotropy ratio of almost 90%. Devices whose transport occurs along the a-axis, however, show much lower anisotropy in gauge factors when strain is applied along different directions, leading to an anisotropy ratio of 50%. Furthermore, ab initio calculations of strain dependent change in resistance showed the same trends of the anisotropy ratio as obtained from experimental results for both electrical transport and strain application directions, which were correlated with bandgap changes and different orbital contributions.

A Combined MPC and PI Control Strategy for Bidirectional Interleaved Totem Pole PFC Converters in Electric Vehicle G2V and V2G Applications

This paper presents an optimized control strategy for a bidirectional interleaved totem pole Power Factor Correction (PFC) converter, employing a combination of Model Predictive Control (MPC) and a Proportional-Integral (PI) controller. The converter’s mathematical model is used to implement the MPC, which ensures a unit power factor during both Grid-to-Vehicle (G2V) and Vehicle-to-Grid (V2G) operations. Meanwhile, the PI controller regulates the DC-side voltage. It is worth noting that the MPC’s design eliminates the need for a comparator to generate the Pulse Width Modulation (PWM) signal, simplifying the control architecture. The proposed control technique’s effectiveness is validated through various simulation scenarios in both G2V and V2G power transfer modes, demonstrating satisfactory performance. This integrated approach provides a robust solution for efficient energy management and high-quality power conversion in bidirectional PFC converters.

Electrospraying Si/SiO x /C and Sn/C nanosphere arrays on carbon cloth for high-performance flexible lithium-ion batteries

Exploring electrode materials with larger capacity, higher power density and longer cycle life was critical for developing advanced flexible lithium-ion batteries (LIBs). Herein, we used a controlled two-step method including electrospraying followed with calcination treatment by CVD furnace to design novel electrodes of Si/Si x /C and Sn/C microrods array consisting of nanospheres on flexible carbon cloth substrate (denoted as Si/Si x /C@CC, Sn/C@CC). Microrods composed of cumulated nanospheres (the diameter was approximately 120 nm) had a mean diameter of approximately 1.5 µm and a length of around 4.0 µm, distributing uniformly along the entire woven carbon fibers. Both of Si/Si/Si x /C@CC and Sn/C@CC products were synthesized as binder-free anodes for Li-ion battery with the features of high reversible capacity and excellent cycling. Especially Si/Si x /C electrode exhibited high specific capacity of about 1750 mA∙h∙g−1 at 0.5 A∙g−1 and excellent cycling ability even after 1050 cycles with a capacity of 1388 mA∙h∙g−1. Highly flexible Si/Si x /C@CC//LiCoO2 batteries based on liquid and solid electrolytes were also fabricated, exhibiting high flexibility, excellent electrical stability and potential applications in flexible wearable electronics.