Scan Rate Research Articles

3D Printing of Hierarchical Structures Made of Inorganic Silicon-Rich Glass Featuring Self-Forming Nanogratings.

Hierarchical structures are abundant in nature, such as in the superhydrophobic surfaces of lotus leaves and the structural coloration of butterfly wings. They consist of ordered features across multiple size scales, and their advantageous properties have attracted enormous interest in wide-ranging fields including energy storage, nanofluidics, and nanophotonics. Femtosecond lasers, which are capable of inducing various material modifications, have shown promise for manufacturing tailored hierarchical structures. However, existing methods, such as multiphoton lithography and three-dimensional (3D) printing using nanoparticle-filled inks, typically involve polymers and suffer from high process complexity. Here, we demonstrate the 3D printing of hierarchical structures in inorganic silicon-rich glass featuring self-forming nanogratings. This approach takes advantage of our finding that femtosecond laser pulses can induce simultaneous multiphoton cross-linking and self-formation of nanogratings in hydrogen silsesquioxane. The 3D printing process combines the 3D patterning capability of multiphoton lithography and the efficient generation of periodic structures by the self-formation of nanogratings. We 3D-printed micro-supercapacitors with large surface areas and a high areal capacitance of 1 mF/cm2 at an ultrahigh scan rate of 50 V/s, thereby demonstrating the utility of our 3D printing approach for device applications in emerging fields such as energy storage.

Effect of Triton X-100 surfactant concentration on the wettability of polyethylene-based separators used in supercapacitors

Polyethylene-based separators are generally unsuitable for aqueous supercapacitors due to their poor wettability with the electrolyte, which impedes ion transport. However, incorporating Triton X-100 (2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethanol) into the aqueous sulfuric acid (H2SO4) electrolyte improves the wettability of polyethylene and facilitates ionic movement through its pores. In this study, Triton X-100 was added to 1.0 M H2SO4 at various concentrations (0.122%–1.210% V/V) to evaluate its impact on supercapacitor performance. Supercapacitors were assembled using activated carbon-filled carbon cloth electrodes, each of the above electrolytes and polyethylene sheet separators. Scanning electron microscopy revealed that the carbon cloth exhibited a uniform fiber distribution and high surface area for activated carbon integration. The polyethylene separator displayed a porous structure with an average pore size of 165 ± 35 nm. Triton X-100 significantly reduced the water contact angle from 101.5° (without surfactant) to 30.2° (with 1.21% V/V Triton X-100), enhancing polyethylene’s wettability. This change from hydrophobic to hydrophilic characteristics enabled the formation of an electrical double layer at the separator/electrolyte interface, improving ionic transport. However, higher Triton X-100 concentrations increased the electrolyte's viscosity, which impeded ion movement. The highest specific capacitance of 55.3 F/g (at a scan rate of 0.005 V s−1) was achieved with 0.488% V/V Triton X-100. The specific capacitance varied with surfactant concentration in a complex manner, influenced by micelle formation and precipitation. These findings were corroborated by cyclic voltammetry and AC impedance spectroscopy.

Investigation of electrical, dielectric, magnetic and electrochemical characteristics of a BaFe12O19/Co0.5Zn0.5Fe2O4 nanocomposite

BaFe12O19 (barium ferrite, i.e., BaF) nanoparticles, Co0.5Zn0.5Fe2O4 (cobalt zinc ferrite, i.e, CZF) nanoparticles and their nanocomposite were synthesized for the investigation of electrical, magnetic, dielectric, and electrochemical properties. The X-ray diffraction (XRD) pattern revealed the formation of hexagonal structure for BaF nanoparticles and cubic structure for CZF nanoparticles with crystallite size of 32.44 nm and 31.30 nm, respectively. Whereas, for nanocomposite, the crystallite size obtained is 34.21 nm were shifting of peaks revealed the formation of nanocomposite. The Fourier transform Infrared (FTIR) spectra revealed the presence of metal-oxygen vibrational peaks for all the samples. The dielectric data revealed the increase in dielectric constant of nanocomposite as compared to pristine CZF whereas, loss reduced for nanocomposite significantly. Single semicircle in Nyquist plot for all the samples revealed the contribution of grain resistance in impedance. The hysteresis loop showed the increase in specific saturation magnetization from 16.963 emu/g to 21.305 emu/g for nanocomposite when compared with pristine BaF. Whereas specific remnant magnetization increased to 10.305 emu/g for nanocomposites. The electrochemical properties presented by Cyclic voltammetry showed the presence of cathodic and anodic peaks which revealed the presence of redox reaction in all samples. The specific capacitance calculated for all samples at different scan rate revealed that a nanocomposite showed highest Cs value 16.43 F/g at 25 mV, whereas it increased to 27.01 F/g, 35.93 F/g and 38.87 F/g with the increase in scan rate to 50 mV, 75 mV and 100 mV, respectively.

Mechanistic Insights into the Potentiodynamic Electrosynthesis of PEDOT Thin Films at a Polarizable Liquid|Liquid Interface.

Conducting polymer (CP) thin films find widespread use, for example in bioelectronic, energy harvesting and storage, and drug delivery technology. Electrosynthesis at a polarizable liquid|liquid interface using an aqueous oxidant and organic soluble monomer provides a route to free-standing and scalable CP thin films, such as poly(3,4-ethylenedioxythiophene) (PEDOT), in a single step at ambient conditions. Here, using the potentiodynamic technique of cyclic voltammetry, interfacial electrosynthesis involving ion exchange, electron transfer, and proton adsorption charge transfer processes is shown to be mechanistically distinct from CP electropolymerization at a solid electrode|electrolyte interface. During interfacial electrosynthesis, the applied interfacial Galvani potential difference controls the interfacial concentration of the oxidant, but not the CP redox state. Nevertheless, typical CP electropolymerization electrochemical behaviors, such as steady charge accumulation with each successive cycle and the appearance of a nucleation loop, were observed. By combining (spectro)electrochemical measurements and theoretical models, this work identifies the underlying mechanistic origin of each feature on the cyclic voltammograms (CVs) due to charge accumulated from Faradaic and capacitive processes as the PEDOT thin film grows. To prevent overoxidation during interfacial electrosynthesis with a powerful cerium aqueous oxidant, scan rates in excess 25 mV·s-1 were optimal. The experimental methodology and theoretical models outlined in this article provide a broadly generic framework to understand evolving CVs during interfacial electrosynthesis using any suitable oxidant/monomer combination.

Insights into the electrochemical performance of manganese dioxide coated metallic foils as potential electrodes for supercapacitors

AbstractManganese dioxide (MnO2) is a promising electrode material for supercapacitors due to its high theoretical specific capacitance. In this study, MnO2 particles were synthesized using a simple hydrothermal method and subsequently coated onto silver, nickel, and aluminum foils via dip coating. The structural, morphological, and functional properties of the resulting MnO2 nanocomposites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FT–IR). Electrochemical impedance spectroscopy (EIS), galvanostatic charge–discharge (GCD), and cyclic voltammetry (CV) were employed to investigate the electrochemical performance of the coated metallic foils. The results demonstrated that MnO2/Ag foils exhibited the highest specific capacitance of 198 F g–1 at a scan rate of 0.25 A g−1, accompanied by excellent cycle stability (89% capacitance retention). This performance surpassed that of MnO2/Ni and MnO2/Al foils, which exhibited maximum specific capacitances of 150 and 101 F g−1, respectively. Additionally, MnO2/Ag foils displayed the highest charge storage capacity, as evidenced by EIS analysis, reaching 4000 Ω, nearly double that of MnO2/Ni and MnO2/Al foils. These findings highlight the potential of cost-effective and high-performance MnO2/Ag foils for widespread applications in energy storage devices such as electrochemical capacitors. Graphical Abstract

Electro‐Oxidation of Ibuprofen and Metoprolol Using a Manganese Oxide Platform

AbstractPharmaceutical compounds, such as ibuprofen and metoprolol, are of increasing concern due to their persistence in the environment and potential adverse effects on human health. In this work, we developed an electrochemical sensor system for the determination of ibuprofen and metoprolol based on a modified manganese oxide nanoparticle (MnO2NPs) on a screen‐printed carbon electrode (SPCE). The characterisation of MnO2NPs modifier was investigated via Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy techniques, Uv/vis spectroscopy, and small‐angle X‐ray scattering spectroscopy. The electrochemical behaviour of the MnO2NPs was studied using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques. The optimum experimental conditions were investigated by examining the effects of scan rates, pH on the CV responses, and electrolytes on the DPV response. The MnO2NPs modified electrode demonstrated enhanced catalytic activity in the electro‐oxidation of both ibuprofen and metoprolol. The oxidation peaks of ibuprofen and metoprolol were observed at +1.14 V and +1.46 V, respectively, for the MnO2NPs/SPCE sensor. The sensor's limit of detection was 3.81 pM and 4.6 pM respectively and its linear response was from 0.97–5.82 pM. Furthermore, interference and stability studies were conducted to evaluate the performance of the MnO2NPs/SPCE sensor under optimum conditions, which resulted in a good performance. The proposed sensor was successfully used for the determination of ibuprofen and metoprolol in the application of real water samples.

So Many Barcodes, So Little Time: A Quality Improvement Project to Improve Scanning of Blood Product Bags

Background Incorrect administration of blood products is a critical concern, occurring once in every 12,000 units transfused in the United States. Blood product documentation and scanning are vital for patient safety, yet difficulties in scanning multiple barcodes on blood transfusion bags often lead to delays and the need for manual overrides. Methods This quality improvement project utilized the PDCA (Plan-Do-Check-Act) cycle of improvement to address blood product scanning in a 495-bed hospital in New York City. Results The scanning rate for blood products increased significantly from 69% in January 2021 to 96% in May 2021, representing a 39% improvement. Subsequently, increased compliance in 2022 demonstrated sustainment of best practices. Conclusions Implementation of the PDCA method led to increased compliance in scanning blood product bags following barcode scanner recalibration.

Research on the laser melting coating process of an AlCoCrFeNi high‐entropy alloy

AbstractLaser cladding technology is an advanced surface modification technique that has gained significant attention in various fields due to its energy savings, efficiency, and environmental friendliness. This paper discusses the preparation of AlCoCrFeNi high‐entropy alloy (HEA) coatings on the surface of a 5083 aluminum alloy using laser cladding technology under the Ar gas conditions. An orthogonal test system was used to optimize the laser cladding process parameters. The microstructure, as well as the mechanical, frictional, and electrochemical properties of the HEA coatings, were comparatively analyzed under the two process conditions S4 and S10. The results indicate that, under S10, the HEA coatings exhibit optimal surface quality. The coatings contained a mixture of Face‐centered cubic (FCC) and Body‐centered cubic (BCC) phases. Microscopic examination revealed three distinct areas: dark, gray, and off‐white. The coatings can significantly improve the wear and corrosion resistance of the alloy substrate. For the best results, it is set the laser power to 200 W, the laser scanning distance to .05 mm, and the laser scanning rate to 1250 mm/s. This present study offers a novel technical foundation for the fabrication of HEA coatings.

Pt–Ni–Co trimetallic nanoparticles anchored on graphene oxide: An effective catalyst for ammonia-borane hydrolysis and direct electrooxidation of ammonia-borane in alkaline solution

In this study, graphene oxide supported platin, nickel and cobalt trimetallic nanoparticles (PtNiCo@GO) were prepared by the impregnation/reduction method. The catalytic performances of PtNiCo@GO catalysts prepared with different atomic ratios were investigated for hydrogen production and electro-oxidation of ammonia-borane (AB). For hydrolysis of ammonia-borane, Pt0.8Ni0.1Co0.1@GO catalyst exhibited higher catalytic activity than Pt0.6Ni0.2Co0.2@GO, Pt0.4Ni0.3Co0.3@GO, and Pt0.2Ni0.4Co0.4@GO. The hydrogen generation rate and turnover frequency values were found to be 540 mL min−1g−1 and 42.8 min−1, respectively, in the experiment conducted at 35 °C, 0.5 mmol AB, and 50 mg Pt0.8Ni0.1Co0.1@GO catalyst. The activation parameters (Ea, ΔH#, and ΔS#) in the catalytic hydrolysis of AB were obtained at 42.22 kJ/mol, 31.95 kJ/mol and −114.82 J/(mol × K), respectively. The effects of the PtNiCo@GO catalyst on AB electro-oxidation were made at a scanning rate of 100 mV/s in the potential range of - 1V/+1V against Ag/AgCl, and chronoamperometry measurements were made at constant potentials of - 0.2V, 0.1V and 0.4V. For cyclic voltammetry and chronoamperometry measurements, 5 mM [Fe(CN)6]3/4 (1 M KCl) redox probe and 1 M NaOH + 50 mM AB solution were used.

Hierarchical nickel phosphide/carbon nanofibers for high performance pseudocapacitors

Nickel phosphide (Ni3P)/Carbon nanofibers (CNFs) with controllable sizes and morphologies are synthesized using micro arc oxidation method combined with thermochemical vapor deposition, with adjustment of different annealing temperatures to control the dimension of CNFs. In this study, we report the in situ formation of transition metal phosphide nanoparticles through the conversion of 1D Ni5TiO7 nanowires. This fabrication strategy ensures the high growth density of CNFs. The initially formed Ni3P nanoparticles boost the catalytic growth of CNFs, which feature a high specific surface area and excellent conductivity. Together with redox electrolyte, the specific capacitance of Ni3P/CNFs based pseudocapacitor (PC) is 114.6 mF cm−2 at a scan rate of 10 mV s−1 and maintains 95.0 % of initial capacity after 10,000 cyclic charging/discharging test. Moreover, such composite based symmetric PCs offer an energy density of as high as 31.6 Wh kg−1 accompanied with a power density of 10.3 kW kg−1. The performance of formed PC devices is comparable to market-available (Li-/Na-) batteries. Therefore, Ni3P/CNFs composite film is a suitable capacitor electrode material for constructing high performance symmetric carbon material based PCs.

Radiosynthesis, Quality Control, and Small Animal Positron Emission Tomography Imaging of 68Ga-labelled Nano Molecules.

Small animal Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) imaging techniques are crucial in preclinical cancer research, necessitating meticulous attention to radiotracer synthesis, quality assurance, and in vivo injection protocols. This study presents a comprehensive workflow tailored to enhance the robustness and reproducibility of small animal PET experiments. The synthesis process in the radiochemistry laboratory using 68Ga is detailed, highlighting stringent quality control and assurance protocols for each radiotracer production. Parameters such as concentration, molar activity, pH, and purity are rigorously monitored, aligning with standards applicable to human studies. This methodology introduces streamlined syringe preparation and a custom-designed 30G cannula for precise intravenous injections into mice. Monitoring of animal health during scanning, including temperature and heart rate, ensures their well-being throughout the procedure. Dosages for PET and SPECT scans are predetermined to balance data acquisition with minimizing radiation exposure to animals and researchers. Similarly, CT scans employ pre-programmed settings to limit radiation exposure, especially pertinent in long-term studies assessing treatment effects. By optimizing these steps, the workflow aims to standardize procedures, reduce variability, and enhance the quality of small animal PET/SPECT/CT imaging. This resource provides valuable insights for researchers seeking to improve the accuracy and reliability of preclinical investigations in molecular imaging, ultimately advancing the field.

Development of a 1D-WO3 and CuO nanocomposite modified electrode for enhanced detection of 2,4-dichlorophenol

A common chlorinated phenol known as 2,4-dichlorophenol (2,4-DCP) was investigated electrochemically using cyclic voltammetry (CV) and square wave voltammetry (SWV). The electrochemical investigation was carried out at 1D nanostructured tungsten dioxide (WO3) and copper (II) oxide (CuO) nanocomposite-modified carbon paste electrode (CPE). The electrode's sensitivity was improved by the WO3/CuO nanocomposite, enabling investigators to more precisely measure the 2,4-DCP's electrochemical characteristics. The hydrothermal method was utilized to synthesize the WO3 NPs. The XRD, AFM, SEM, and EDS techniques were used to characterize the nanocomposite and WO3 NPs. Numerous parameters have been studied, including pH, concentration variation, scan rate variation, and accumulation time. Samples of soil, fruits, and vegetables were examined using the fabricated WO3/CuO/CPE. In the concentration range of 7.0 × 10−8 M to 2.6 × 10−7 M, a linear relationship was established along with the lower limit of detection of 0.17 × 10−8 M and the limit of quantification of 0.57 × 10−7 M. The 0.2 M phosphate buffer (PB) of pH 10.4 increased the peak current, which contributed to the WO3/CuO/CPE sensor's sensing performance and was highly sensitive with respect to 2,4-DCP detection. Anodic peak current was observed for the WO3/CuO/CPE is at -7.45 µA whereas for unmodified CPE is at -1.31 µA. According to the findings, the nanostructured WO3 and CuO nanocomposite showed exceptional sensitivity in identifying the electrochemical characteristics and reactions of 2,4-DCP.

Attachment of ρ-aminobenzene sulphonic acid into magnetic Fe3O4 reduced graphene oxide and its application for sensitive determination of L-tryptophan in milk and banana samples

This paper reports the attachment of p-aminobenzene sulfonic acid on the surface of magnetic Fe3O4-reduced graphene oxide. Different techniques including FTIR, UV, EIS, XRD, and SEM imaging were employed for characterization. The finding indicates the successful attachment of the p-aminobenzene sulfonic acid to the surface. The synthesized material was used to make a carbon paste electrode for the determination of the essential amino acid L-tryptophan (L-Try). EIS and CV characterization of the electrode further confirms the attachment of the acid. Of the different electrode materials used, the p-aminobenzene sulfonic acid attached magnetic Fe3O4 reduced graphene oxide showed very good electrocatalytic activity. The scan rate study showed that the electrode process is an adsorption-controlled one. The prepared electrode material gave a linear curve for 0.001 μM to 10 μM L-Try concentrations, and the limit of detection and limit of quantification were 0.26 nM and 0.78 nM, respectively. Furthermore, the electrode material was employed for the determination of L-Try in a milk and banana sample.

Electrochemical grafting of diazonium salts on silica-terminated versus H-terminated silicon

Diazonium salts are one of the most widely used molecules for functionalising electrode surfaces, due to their high reactivity toward a range of different electrodes but have mostly been studied on carbon and gold. Recent work has demonstrated that diazonium salts can be reduced on silica-terminated silicon (Si/SiOx) despite silica (SiOx) being an electrically insulating material, but this interesting phenomenon was only demonstrated on one specific crystal orientation, Si(111) using specific diazonium salts molecules – a more complete understanding of the electrochemical properties of these silica-terminated silicon electrodes remains unclear. In this work, we develop a thorough understanding of the reduction of diazonium compounds on silica-terminated silicon using silicon with different crystal orientation and using nano-structured silicon surfaces that are chemically etched to simultaneously expose different crystal orientations. A comparison between the reduction process on oxide free silicon (Si–H) and silica-terminated Si is then made to reveal the effect of the crystal orientation (amorphous vs crystalline) and the insulating nature of the distal surface (Si‒H vs SiOx) on the reduction process. Results show that diazonium salts form, well-packed thin films on silica-terminated silicon regardless of the crystal orientation of the silicon. The rate of diazonium reduction was found to be sensitive to the crystal orientation of Si only when the diazonium salts are in direct contact with the crystal plane (i.e. in contact with Si–H) as opposed to when there is a thin layer of native amorphous oxide material in between. The reduction rate is sufficiently slow on silica-terminated silicon that at slow scan rates, the system reaches a steady state current and become diffusion controlled. This is not observed on oxide-free silicon electrodes which are observed to be governed by a kinetically driven mechanism. These findings deepen our understanding of the electrochemical activity of silica-terminated silicon surfaces which are widely used in solar cells, electronics, chemical and biosensors.

Advanced Electrochemical Monitoring of Carbendazim Fungicide in Foods Using Interfacial Superassembly of NRPC/NiMn Frameworks.

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%.

Decoding electrochemical dynamics: Examining the potential of GO/Cu1-xSrxCr2O4 nanocomposite for high-performance supercapacitor energy storage

In this study, pure Cu1-xSrxCr2O4/GO nanoparticles were successfully synthesized via a simple precipitation route followed by calcination at 70 °C for 2 h, resulting in a high-performance supercapacitor nanoelectrode material. Characterization techniques confirmed the formation and properties of the synthesized materials. X-ray diffraction (XRD) analysis revealed the crystalline structure of the nanocomposite, with the d-spacing value of GO changing to 7.6 Å and the presence of peaks indicating the Cu1-xSrxCr2O4 phase. The average crystalline sizes were found to be 13.5 nm for GO, 16.15 nm for CuCr₂O₄, and 21.2 nm for the Cu1-xSrxCr2O4/GO nanocomposite. Scanning electron microscopy (SEM) demonstrated the highly porous nature of the samples, with average grain sizes of 30 nm, 25 nm, and 27.4 nm for GO, CuCr₂O₄, and Cu1-xSrxCr2O4/GO, respectively. Elemental analysis using energy-dispersive X-ray spectroscopy (EDS) confirmed the presence of copper, chromium, and oxygen, along with minor impurities. Raman spectroscopy indicated an increased defect density in the Cu1-xSrxCr2O4/GO nanocomposite, with an ID/IG ratio of 1.57 compared to 1.01 for GO. Photoluminescence (PL) analysis showed a bandgap of 3.65 eV for GO and 2.49 eV for the Cu1-xSrxCr2O4/GO nanocomposite. Electrochemical characterization included electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The EIS analysis showed that the Cu1-xSrxCr2O4 /GO nanocomposite had a lower charge transfer resistance (Rct) of 1.29 Ω compared to GO and CuCr2O4, indicating higher conductivity. The maximum specific capacitance of the Cu1-xSrxCr2O4 /GO nanocomposite was 1935.8 F/g at a scan rate of 3 mV/s in 1 M KOH electrolyte, significantly higher than that of GO alone (480.190 F/g). This study demonstrates the potential of Cu1-xSrxCr2O4/GO nanocomposites as efficient supercapacitor electrode materials, showcasing enhanced capacitance and conductivity due to the synergistic effects of the components.

Use of magnetic fields to impact glass-transition and crystallization during manufacturing of ZBLAN optical fibers

ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) is the most stable glass among the Heavy Metal Fluoride (HMF) family and has a wide range of applications in medical industry, telecommunication, IR transmission, among others. But, due to crystal formation while manufacturing of ZBLAN fiber its theoretical minimum loss has not been achieved yet. Some techniques such as high cooling rate and microgravity conditions have been utilized to reduce the crystal formation but are challenging to implement during manufacturing of these fibers. Alternatively, magnetic field (MF), also a body force like gravity, is expected to influence the crystal formation mechanism and glass kinetics. In this work, ZBLAN glass is processed under magnetic fields of various intensities while simulating fiber drawing manufacturing process conditions. Then, the processed ZBLAN is analyzed using Differential Scanning Calorimetry (DSC) at varying scanning rates. Various glass kinetics parameters such as activation energy, fragility, and preferred crystallization mechanism in terms of Avrami parameter (n) have been analyzed. The glass transition temperature (Tg) increases for a given sample as scanning rate (β) increases. Samples processed under varying magnetic fields, at the same scanning rate, displayed higher glass transition temperatures. Also, when the magnetic field increases, the activation energy required for glass transition decreases, and the fragility index (m) decreases. There is also a preference for surface crystallization over volume crystallization. These results encourage application of magnetic fields for reducing crystal formation while processing ZBLAN glass.

Preparation and Conductivity Analysis of LLTO Nanofiber‐Incorporated PEO‐PVDF‐HFP‐LiClO4 Solid Polymer Electrolytes for High‐Voltage Lithium Metal Batteries

ABSTRACTThis work focuses on the development of a composite polymer electrolyte (CPE) for all‐solid‐state lithium metal batteries (ASSLMBs), integrating LLTO nanofibers into a PEO (polyethylene oxide)‐PVDF‐HFP (poly(vinylidene fluoride‐cohexafluoropropylene)) matrix with LiClO4 as the lithium salt. The PEO has high ionic conductivity and flexibility, and the PVDF‐HFP has high mechanical strength and electrochemical stability. Therefore, the resulting composite has improved electrochemical performance and mechanical properties. Incorporating LLTO nanofibers enhances ionic conductivity due to the one‐dimensional ion transport pathways provided by the nanofibers while maintaining mechanical integrity and air stability, overcoming the challenges associated with conventional fillers. The prepared CPE demonstrates exceptional electrochemical stability up to 5.1 V versus Li/Li+, making it suitable for high‐voltage applications over traditional polymer electrolytes. The optimized CPE with 15 wt% LLTO provides the ionic conductivity of 1.1 × 10−5 S cm−1 at room temperature and reaches 1.46 × 10−4 S cm−1 at 80°C. The assembled LiNi1/3Mn1/3Co1/3PO4||PEO‐PVDF‐HFP‐LiClO₄‐LLTO||Li based 2032 coin cell worked in between 3 and 4.8 V versus Li/Li+ potential window without any electrolyte decomposition from 0.5 to 5 mV/s scan rates. Similarly, the fabricated LiFePO₄||PEO‐PVDF‐HFP (1:2)‐LiClO4‐LLTO (15 wt%)||Li cell provides an initial capacity of 149 mAh g−1 at 0.1 C and 85 mAh g−1 at 0.5 C, exploring its potential for lithium metal batteries. Overall, this work offers a promising pathway for developing advanced solid polymer electrolytes for next‐generation lithium metal batteries, which combine high ionic conductivity, excellent electrochemical performances, and robust mechanical properties.

Strengths and Weaknesses of Elimination Voltammetry with Linear Scan

Electrochemical methods have undergone many important developments initiated by efforts to increase the sensitivity, selectivity, and stability (S&S&S) and to understand the underlying electrode processes. To meet these goals, there are hardware solutions with applications of new technologies and materials, and software solutions utilizing existing instrumentation. The article presents a viable, easy-to-implement software solution to the main shortcomings of linear sweep voltammetry (low sensitivity, high share of the capacitive component of the current, and the problem of overlapping signals) in the form of elimination voltammetry with a linear scan (EVLS). Based on the different dependences of the individual currents that make up the total voltammetric current (diffusion, charging, kinetics, and various irreversible components) on the scan rate, EVLS can eliminate or preserve particular current components. Increased sensitivity and selectivity can be expected especially in the case of a fully adsorbed electroactive particle subjected to an irreversible electrode process when the elimination of kinetic and capacitive current while preserving the diffusion current provides a theoretically confirmed peak-counter peak signal. EVLS is applicable for testing changes in the polarized electrode/electrolyte interface using EVLS functions eliminating the diffusion component of the current and preserving the kinetic and capacitive currents, which should ensure zero current conduction for a purely diffusion-controlled Nernstian-type reversible process. We point out the strengths, opportunities, and weaknesses of EVLS. Nevertheless, EVLS offers a new tool that contributes to a better understanding of electrochemical processes and their mechanisms.

Field-deployable pencil lead-based electrochemical cell for the determination of the emerging contaminant and antidepressant drug venlafaxine in wastewater

Screening and quantification of emerging contaminants in water is of enormous relevance due to its scarcity and harmful effects on aquatic life and human health. We present a simple and cost-effective electrochemical cell for determination of the antidepressant venlafaxine, an emerging contaminant included in the EU Watch List 2022. The cell consists of pencil leads used as electrodes and a microcentrifuge tube. Modification of the working electrode with carbon nanomaterials improved the signal. Cell-related parameters (e.g., type of pencil leads or electroactive area) as well as experimental (e.g., pH, accumulation potential and time, and scan rate) were thoroughly optimized. The adsorptive nature of venlafaxine process allowed the use of adsorptive stripping square wave voltammetry methodology to increase the sensitivity. Under optimized variables, a linear range from 0.8 to 10 μmol L-1, with a correlation coefficient of 0.996 and a sensitivity of 1.48 μmol L-1, a LOD of 0.4 μmol L-1 and a RSD of 2.4 % were achieved. Selectivity was also studied, especially with respect to the main metabolite o-desmethylvenlafaxine. The methodology distinguishes its signal from that of the main compound, allowing its determination. A similar linear range was obtained for the metabolite, with a LOD of 0.6 μmol L-1. The platform developed was applied for venlafaxine quantification in spiked wastewaters from the Febros plant in Portugal, obtaining satisfactory recoveries. Furthermore, the versatility of pencil leads made it possible to combine them with modified paper for sampling and buffering in order to decentralize the determination, showing promising results.