Search Results (16,918)

Environmental impacts and resource availability are significant concerns for the future of lithium-ion batteries. This study focuses on developing novel fluorine-free electrolytes compatible with aqueous-processed cobalt-free cathode materials. The new electrolyte contains lithium 1,1,2,3,3-pentacyanopropenide (LiPCP) salt. After screening various organic carbonates, a mixture of 30:70 wt.% ethylene carbonate and dimethyl carbonate was chosen as the solvent. The optimal salt concentration, yielding the highest conductivity of 9.6 mS·cm⁻¹ at 20 °C, was 0.8 mol·kg⁻¹. Vinylene carbonate was selected as a SEI-stabilizing additive, and the electrolyte demonstrated stability up to 4.4 V vs. Li+/Li. LiFePO₄ and LiMn_0.6Fe_0.4PO₄ were identified as suitable cobalt-free cathode materials. They were processed using sodium carboxymethyl cellulose as a binder and water as the solvent. Performance testing of various cathode compositions was conducted using cyclic voltammetry and galvanostatic cycling with the LiPCP-based electrolyte and a standard LiPF6-based one. The optimized cathode compositions, with an 87:10:3 ratio of active material to conductive additive to binder, showed good compatibility and performance with the new electrolyte. Aqueous-processed LiFePO₄ and LiMn_0.6Fe_0.4PO₄ achieved capacities of 160 mAh·g⁻¹ and 70 mAh·g⁻¹ at C/10 after 40 cycles, respectively. These findings represent the first stage of investigating LiPCP for the development of greener and more sustainable lithium-ion batteries. Full article

Escitalopram (ESC) is commonly prescribed as an antidepressant to enhance serotonin levels in the brain, effectively addressing conditions such as depression and anxiety. The COVID-19 pandemic, along with ongoing mental health crises, has exacerbated the prevalence of these disorders, largely due to factors such as social isolation, fear of the virus, and financial difficulties. This study presents the enhancement of a glassy carbon electrode (GC) through the incorporation of hydrochar (HDC) derived from spent coffee grounds and copper nanoparticles (CuNPs) for the detection of ESC in synthetic urine. Characterization of the nanocomposite was conducted using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and cyclic voltammetry (CV). The analytical parameters were systematically optimized, and a sensing platform was utilized for the quantification of ESC via square-wave voltammetry (SWV). The established linear range was found to be between 1.0 µmol L⁻¹ and 50.0 µmol L⁻¹, with a limit of detection (LOD) of 0.23 µmol L⁻¹. Finally, an electrochemical sensor was employed to measure ESC levels in synthetic urine, yielding recovery rates ranging from 91.7% to 94.3%. Consequently, the HDC-CuNPs composite emerged as a promising, sustainable, and cost-effective alternative for electroanalytical applications. Full article

Electrostatic spraying is considered an effective means to improve the efficacy of pesticide application and reduce pesticide consumption. However, the effectiveness of electrostatic spraying needs further validation in greenhouse environments, especially in long-range air-assisted spraying scenarios. A waist-shaped charging device has been improved to obtain a maximum charge-to-mass ratio of 4.4 mC/kg at an applied voltage of 6 kV in a laboratory setting, representing an increase of approximately 84.9% compared to a commercial circular charging electrode with a fan-shaped nozzle. A comparative air-assisted spray test between electrostatic deactivation (EDAS) and electrostatic activation (EAAS) was conducted on greenhouse tomato crops using a single hanging track autonomous sprayer equipped with a pair of waist-shaped charging devices. The results showed that EAAS yielded an overall average coverage of 28.4%, representing a significant 10.9% improvement over the 25.6% coverage achieved with EDAS. The overall coefficient of variation (CV) for EDAS and EAAS was 62.0% and 48.0%, respectively. Within these, the CV for the average coverage of the sample set reflecting axial distribution uniformity was 33.4% and 31.4%, respectively. Conversely, the CV for the average coverage of the sample group reflecting radial distribution uniformity was 33.7% and 17.9%, respectively. The results indicate that the waist-shaped charging device possesses remarkable charging capabilities, presenting favorable application prospects for long-range air-assisted spraying in greenhouses. The electrostatic application has a positive effect on enhancing the average coverage and improving the overall distribution uniformity. Notably, it significantly improves the radial distribution uniformity of the air-assisted spray at long range, albeit with limited improvement in the axial distribution uniformity. Full article

R&D in the area of high-temperature symmetrical electrochemical devices is needed to meet the challenges of hydrogen energy. In the present study, the effect of Fe₂O₃ and CuO sintering aids on the electrochemical properties of the highly conductive solid electrolyte La_0.8Sr_0.2Ga_0.8Mg_0.2O_3−δ and La_0.6Sr_0.4FeO_3−δ electrodes for symmetrical solid oxide fuel cells was investigated. It is shown that the use of sintering aids leads to an improvement in grain boundary conductivity and allows us to reduce the sintering temperature to obtain a dense electrolyte with the same level of conductivity. It is shown for the first time that the nature of the sintering aids and the sintering temperature affect the La_0.6Sr_0.4FeO_3−δ electrode activity differently depending on the gas environment (air or hydrogen). On the basis of the analysis of the impedance spectra by the distribution of relaxation times, assumptions were made about the nature of the rate-determining steps of hydrogen oxidation and oxygen reduction. It is shown that the nature of the rate-determining steps can change depending on the electrode sintering temperature. It was found that among the studied electrodes, La_0.6Sr_0.4FeO₃−_δ with 3 wt.% Fe₂O₃ sintered at 1050 °C is optimal in terms of activity in oxidizing and reducing atmospheres. Full article

A new approach to developing structural sodium batteries capable of operating in ambient-temperature conditions has been successfully achieved. The developed multifunctional structural electrolyte (SE) using poly(ethylene oxide) (PEO) as a matrix integrated with succinonitrile (SN) plasticizers and glass-fiber (GF) reinforcements identified as GF_PEO-SN-NaClO₄ showed a tensile strength of 32.1 MPa and an ionic conductivity of 1.01 × 10⁻⁴ S cm⁻¹ at room temperature. It displayed a wide electrochemical stability window of 0 to 4.9 V and a high sodium-ion transference number of 0.51 at room temperature. The structural electrode (CF|SE) was fabricated by pressing the structural electrolyte with carbon fibers (CFs), and it showed a tensile strength of 72.3 MPa. The fabricated structural battery half-cell (CF||SE||Na) demonstrated good cycling stability and an energy density of 14.2 Wh kg⁻¹, and it retained 80% capacity at the end of the 200th cycle. The cycled electrodes were observed using scanning electron microscopy, which revealed small dendrite formation and dense albeit uniform deposition of the sodium metal, helping to avoid a short-circuit of the cell and providing more cycling stability. The developed multifunctional matrix composites demonstrate promising potential for developing ambient-temperature sodium structural batteries. Full article

This paper presents a fundamental study of electro-thermo-convective flows within a layer of dielectric liquid subjected to both an electric field and a thermal gradient. A low-conductivity liquid enclosed between two horizontal electrodes and subjected to unipolar charge injection is considered. The interplay between electric and thermal fields ignites complex physical interactions within the flows, all governed by a set of coupled electro-thermo-hydrodynamic equations. These equations include Maxwell, Navier–Stokes, and energy equations and are solved numerically using an in-house code based on the finite volume method. Electro-thermo-convective flows are driven by two dimensionless instability criteria: Rayleigh number Ra and the stability parameter T, and also by the dimensionless mobility parameter M and Prandtl number Pr. The electric Nusselt number (Ne) analogue to the Nusselt number (Nu) in pure thermal problems serves as an indicator to monitor the shift from a thermo- to an electro-convective flow and its eventual evolution into unsteady, and, later, chaotic flow. This change in regime is observed by tracking the electric Nusselt number’s behavior as a function of the stability parameter (T), for different values of the non-dimensional parameters (M, Ra, and Pr). The important role of mobility parameter M for the development of the flow is shown. The flow structure during different development stages in terms of the number of convective cells is also discussed. Full article

A simple, sensitive and reliable sensing system based on nitrogen-rich porous carbon (NRPC) and transition metals, NRPC/Ni, NRPC/Mn and NRPC/NiMn was developed and successfully applied as electrode materials for the quantitative determination of carbendazim (CBZ). The synergistic effect of NRPC and bimetals with acceptable pore structure together with flower-like morphology resulted in producing a highly conductive and interconnected network in NRPC/NiMn@GCE, which significantly enhanced the detection performance of CBZ. The electrochemical behavior investigated by cyclic voltammetry (CV) showed improved CBZ detection for NRPC/NiMn, due to the controlled adsorption/diffusion process of CBZ by the NRPC/NiMn@GCE electrode. The influences of various factors such as pH, NRPC/NiMn concentration, CBZ concentration and scan rate were studied. Under optimal conditions, 0.1 M phosphate-buffered saline (PBS) with a pH of 7.0 containing 30 µg/mL NRPC/NiMn, a favourable linear range detection of CBZ from 5 to 50 µM was obtained. Moreover, a chronoamperometric analysis showed excellent repeatability, reproducibility and anti-interfering ability of the fabricated NRPC/NiMn@GCE sensor. Furthermore, the sensor showed satisfactory results for CBZ detection in real samples with acceptable recoveries of 96.40–104.98% and low RSD values of 0.25–3.45%. Full article

Background: Musculoskeletal disorders such as cervicogenic headaches present with suboccipital muscle hypertonicity and trigger points. One manual therapy intervention commonly used to target the suboccipital muscles is the suboccipital release technique, previously related to positive systemic effects. Therefore, this study aimed to determine the immediate and short-term effects of the Suboccipital Release Technique (SRT) on brainwave activity in a subgroup of healthy individuals. Methods: Data were collected from 37 subjects (20 females and 17 males, with a mean age of 24.5). While supine, the subjects underwent a head hold followed by suboccipital release. A total of four 15 s electroencephalogram (EEG) measurements were taken and a Global Rating of Change Scale was used to assess self-perception. Results: There was a statistically significant difference (p < 0.005) in various band waves under the following electrodes: AF3, F7, F3, FC5, T7, P7, O1, O2, P8, T8, and FC6. An 8-point range in the Global Rating of Change Scores with a mean score of 1.649 (SD = 1.719 and SE = 0.283) supported the hypothesis of a self-perceived benefit from the intervention. Conclusions: The results of this study indicate that the suboccipital release technique significantly affects brain wave activity throughout different brain regions. This change is likely not the result of any placebo effect and correlates highly with the subject’s self-perception of a change following the intervention. These findings support the clinical use of the suboccipital release technique when a centralized effect is desired. Full article

While fossil fuels continue to be used and to increase air pollution across the world, hydrogen gas has been proposed as an alternative energy source and a carrier for the future by scientists. Water electrolysis is a renewable and sustainable chemical energy production method among other hydrogen production methods. Hydrogen production via water electrolysis is a popular and expensive method that meets the high energy requirements of most industrial electrolyzers. Scientists are investigating how to reduce the price of water electrolytes with different methods and materials. The electrolysis structure, equations and thermodynamics are first explored in this paper. Water electrolysis systems are mainly classified as high- and low-temperature electrolysis systems. Alkaline, PEM-type and solid oxide electrolyzers are well known today. These electrolyzer materials for electrode types, electrolyte solutions and membrane systems are investigated in this research. This research aims to shed light on the water electrolysis process and materials developments. Full article

Urine analysis represents a crucial diagnostic technique employed in clinical laboratories. Creatinine and uric acid in urine are essential biomarkers in the human body and are widely utilized in clinical analysis. Research has demonstrated a correlation between the normal physiological concentrations of creatinine and uric acid in urine and an increased risk of hypertension, cardiovascular diseases, and kidney disease. Furthermore, the pH of urine indicates the body’s metabolic processes and homeostatic balance. In this study, an integrated multi−channel electrochemical sensing system was developed, combining electrochemical analysis techniques, microelectronic design, and nanomaterials. The architecture of an intelligent medical detection system and the production of an interactive interface for smartphones were accomplished. Initially, multi−channel selective electrodes were designed for creatinine, uric acid, and pH detection. The detection range was 10 nM to 100 μM for creatinine, 100 μM to 500 μM for uric acid, and 4 to 9 for pH. Furthermore, interference experiments were also conducted to verify the specificity of the sensors. Subsequently, multi−channel double−sided sensing electrodes and function−integrated hardware were designed, with the standard equations of target analytes stored in the system’s read−only memory. Moreover, a WeChat mini−program platform was developed for smartphone interaction, enabling off−body detection and real−time display of target analytes through smartphones. Finally, the aforementioned electrochemical detection electrodes were integrated with the smart sensing system and wirelessly interfaced with smartphones, allowing for intelligent real−time detection in primary healthcare and individual household settings. Full article

High-voltage cables will continue to operate for a period of time in the event of a small current arc fault, which poses a risk of fire. Two simulated ignition methods, moving electrode and melting fuses, are proposed to analyze the ignition characteristics of low-current arcs. The ignition test was carried out, and the combustion effect was compared. The results indicate that the moving electrode ignition method can achieve long-distance arc ignition test when the current is small and is suitable for simulating the arc ignition situation of cable outer protective layer damage. By controlling the movement speed, it can be ensured that the arc will not be interrupted during the electrode movement process. However, the arc is difficult to sustain using the fuse melting method when the current is small and the distance is long. The fuse melting method is suitable for simulating insulation breakdown situations. The results show that the critical arc duration for cable ignition under five different current conditions of 2–10 A is 28 s, 21 s, 14 s, 9 s, and 4 s, respectively. The maximum height of the cable flame under 2–10 A arc current is 9–52 cm and 16–63 cm, respectively, when the arc duration is 50 s and 100 s. The self-ignition time of the cable after the arc extinguishing is 8–95 s and 14–261 s, respectively. The maximum temperature of the cable flame is positively correlated with arc current, and the maximum flame temperature of the cable under 2–10 A arc current is 540–980 °C. Based on the actual current monitoring data in cable tunnels, the research results can provide reference for the risk assessment and protection of cable tunnel fires. Full article

A mixed-metal ternary chalcogenide, cobalt molybdenum telluride (CMT), has been identified as an efficient tri-functional electrocatalyst for seawater splitting, leading to enhanced oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR). The CMT was synthesized by a single step hydrothermal technique. Detailed electrochemical studies of the CMT-modified electrodes showed that CMT has a promising performance for OER in the simulated seawater solutions, exhibiting a small overpotential of 385 mV at 20 mA cm⁻², and superior catalyst durability for prolonged period of continuous oxygen evolution. Interestingly, while gas chromatography analysis confirmed the evolution of oxygen in an anodic chamber, it showed that there was no chlorine evolution from these electrodes in alkaline seawater, highlighting the novelty of this catalyst. CMT also displayed remarkable ORR activity in simulated seawater as indicated by its four-electron reduction pathway forming water as the dominant product. One of the primary challenges of seawater splitting is chlorine evolution from the oxidation of dissolved chloride salts. The CMT catalyst successfully and significantly lowers the water oxidation potential, thereby separating the chloride and water oxidation potentials by a larger margin. These results suggest that CMT can function as a highly active tri-functional electrocatalyst with significant stability, making it suitable for clean energy generation and environmental applications using seawater. Full article

The doping process is a unique method of changing the microstructure of a material, influencing its mechanical, thermal, and optical properties. Typically, the doping process is carried out via chemical reagents. In this work, we present a “green” method of doping photochromic TiO₂ via low-temperature plasma. The doping agent was the electrode material that was sputtered during plasma burning. The process of electrode sputtering is confirmed by the emission spectroscopy data of the plasma zone and the mass loss of the electrodes. The doping process was confirmed by X-ray, Raman spectroscopy, and XPS analyses. The role of the dopant nature and the action of diaphragm discharge in improving the photochromic properties of titanium dioxide is considered. Full article

We present a transparent memristor with a rough-surface (RS) bottom electrode (BE) with enhanced performance and reliability for a gasistor, which is a gas sensor plus a memristor, and its application in this paper. The transparent memristor, with an RS BE, exhibited low forming voltages (0.8 V) and a stable resistive switching behavior, with high endurance and an on/off ratio of about 125. This improvement is due to the better control of the electric field distribution and the oxygen vacancy concentration when applying the RS BE to transparent memristors. Maintaining the stability of the conducting filament in an ambient air environment for extended periods of time is crucial for the application of memristors as gasistors. The memristor with an RS BE demonstrates an ability to sustain a stable-current state for approximately 10⁴ s. As a result, it is shown that the proposed transparent memristor with an RS BE can significantly enhance the device’s reliability for gasistor applications. Full article

Solar-driven CO₂ conversion into high-value-added chemicals, powered by photovoltaics, is a promising technology for alleviating the global energy crisis and achieving carbon neutrality. However, most of these endeavors focus on CO₂ electroreduction to small-molecule fuels such as CO and ethanol. In this paper, inspired by the photosynthesis of green plants and artificial photosynthesis for the electroreduction of CO₂ into value-added fuel, CO₂ artificial photosynthesis for the electrocarboxylation of bromobenzene (BB) with CO₂ to generate the value-added carboxylation product methyl benzoate (MB) is demonstrated. Using two series-connected dye-sensitized photovoltaics and high-performance catalyst Ag electrodes, our artificial photosynthesis system achieves a 61.1% Faraday efficiency (FE) for carboxylation product MB and stability of the whole artificial photosynthesis for up to 4 h. In addition, this work provides a promising approach for the artificial photosynthesis of CO₂ electrocarboxylation into high-value chemicals using renewable energy sources. Full article