Search

In this paper, the electrochemical behaviors of Pb(II) and Pr(III) were investigated on W electrode in LiCl–KCl melts, respectively. The results illustrated that the reduction of Pb(II) and Pr(III) was a one step process. When the PbCl2 and PrCl3 co-existed in the molten salt, the cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry illustrated that four kinds of Pb-Pr intermetallic compounds were formed at 773 K. Whereafter, the electrochemical behavior of Pr(III) on liquid Pb cathode was studied by cyclic voltammetry in LiCl–KCl melts, and the result showed that only one kind of Pb-Pr intermetallic compound was formed at 773 K. The Pr element was extracted by galvanostatic and potentiostatic electrolysis with the assistance of Pb cathode in LiCl–KCl–PrCl3 melts, respectively. Finally, the obtained alloys were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and the result illustrated that the prepared intermetallic compound mainly is Pb3Pr. [ABSTRACT FROM AUTHOR]

Reasonable design and synthesis of high-efficiency nanocatalysts are of great significance for the electrocatalytic analysis of fungicides. In this paper, La-doped Nd2O3 (La-Nd2O3) nanomaterials are synthesized by a hydrothermal method and characterized via SEM, TEM, EDS, XPS and XRD. The results confirm that the trigonal Nd2O3 and La-Nd2O3 are successfully synthesized, and La is localized on the surface of the Nd2O3 lattice. Compared with Nd2O3, La-Nd2O3 nanomaterials have a larger surface area. In addition, the prepared Nd2O3 and La-Nd2O3 catalysts coated on a carbon paste electrode (CPE) are used as working electrodes to investigate their electrochemical performance for carbendazim (CBZ). Probably due to the synergistic electronic transfer process and dual-function effects of La-Nd2O3, the La-Nd2O3 modified electrode exhibits a stronger redox signal and faster electron transfer rate, thus resulting in superior electrocatalytic activity against CBZ. The proposed CBZ sensor produces a wide linear range of 0.08 to 50 μM and a low detection limit (0.027 μM, S/N = 3) by differential pulse voltammetry (DPV). Moreover, the La-doped catalyst has a long-term electrochemical activity and catalytic stability under steady state conditions, which indicates that La-Nd2O3 is a promising catalyst in electrocatalysis and sensing applications. [ABSTRACT FROM AUTHOR]

The microstructures with spherical end have been widely applied in micromachining and measurement. In this paper, a microelectrode with spherical end was fabricated combining electrochemical etching with spark discharge machining. Firstly, the formation mechanism of micro spherical electrode was simulated by molecular dynamics LAMMPS, and the energy model of the spherical end was established to guide machining micro spherical electrode. Secondly, on the basis of cylindrical microelectrode, the electrode tip was melted by spark discharge. Simultaneously, the molten electrode formed a spherical end due to surface tension in deionized water. Finally, sets of experiments were carried out to discuss the influence of polarity, applied voltage, and pulse width on the diameter ratio of spherical end to electrode tip. By using optimal machining parameters, the micro spherical electrode with a diameter of 21.25 μm and a coaxial error of 0.9 μm can be obtained, and the diameter ratio is almost 2. [ABSTRACT FROM AUTHOR]

Manufacturing stable and thin air electrodes for flexible Zn-air batteries becomes increasingly important and remains challenge. Here, we report low-cost mechanical calendering to fabricate thin gas-diffusion layers (GDL), catalytic layers (CL) and then heat pressing together. Finally, cylindrical and other sizes of flexible air electrodes are produced without the use of commercially expensive carbon cloth or carbon papers. By assembling the flexible air cathodes with anode Zn-In-Bi alloy powders or Zn foils, alkaline gel electrolytes and membranes, two kinds of Zn-air cells are assembled for performance evaluation. Results reveal that the LR6 Zn-air cells show a capacity of 5300–5400 mAh and an energy density of 340 Wh·kg−1 at 100 mA, having a double discharge capacity compared to the same size alkaline ZnMnO 2 cells. Under a high drain rate of 1000 mA, the capacity and utilization of the Zn alloy powder remain 2750 mAh and 372 mAh·g−1, respectively. The flexible pouch Zn-air cells exhibit excellent charge-discharge performance under conditions of each cycle with 10 min at 2 mA cm−2. The discharge voltage is maintained in the range of 1.25–1.30 V within 120 cycles while the charge voltage is 2.00–2.05 V. These results demonstrate that the thin air cathodes can satisfy the high bending requirements for cylindrical LR6 size cells and flexible pouch Zn-air cells, as well as have high mechanical stability and electrochemical performance. Electrochemical impedance spectroscopies of the air cathodes and Zn-air cells are also examined. [Display omitted] • Thin flexible air cathodes are prepared via calendaring and heat pressing without including commercial carbon cloth/papers. • The air cathodes show good ORR activities with nano NiCo 2 O 4 catalysts having close four-electron-transfer mechanism. • LR6 Zn-air cells exhibit excellent discharge profiles with a capacity of 5300-5400 mAh and energy density of 340 Wh kg-1. • Pouch Zn-air cells with flexible air cathodes show good charging-discharging performance at 2 mA cm-2. [ABSTRACT FROM AUTHOR]

State-of-the-art electrochemical applications have recently employed various activated carbons combined with transition metal oxides as electrode materials, which exhibit superior conductivity and tailored porosity to offer rapid electron transfer. In this study, Bauhinia vahlii dead fruit-derived carbon (BVFC) integrated with cobalt oxide (Co3O4) nanoparticles was used to detect 4-nitrophenol (4-NP). The Co3O4@BVFC composite was characterized using various spectral and analytical techniques, including XRD, Raman, BET, TGA, FE-SEM, TEM and XPS. Under optimum experimental conditions, the Co3O4@BVFC-modified GCE revealed a wide linear range (0.01–140 μM), a low detection limit (5 nM), and high sensitivity (18.236 μA μM−1 cm−2) towards 4-NP detection with considerable selectivity. The excellent sensing ability of the composite was mainly due to the higher surface area and the synergistic effect between Co3O4 and BVFC. Furthermore, the Co3O4@BVFC-modified GCE applied in the real-time analysis of 4-NP in water bodies showed satisfactory recovery results (±96.50–98.60%). Results show that Co3O4@BVFC is a good candidate for 4-NP detection. [ABSTRACT FROM AUTHOR]

The irreversible phase transition of LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode materials easily occurs in high voltage (> 4.5 V) charging processes, which aggravates the corrosion of electrolyte on the materials and seriously affects the safety and cycling performance of lithium-ion batteries. In this paper, K and Cl ions were dual-doped into NCM523 by a high-temperature solid state method, and then Al2O3 was coated on the surface of the NCM523 by a hydrothermal method to obtain the modified cathode materials. The crystal structure, morphology and surface state of the modified materials were analyzed, and the electrochemical performance was tested under high cut-off voltage (4.6 V). The results show that when the content of K and Cl dual-doping and Al2O3 coating are 1 mol.% and 2 wt.%, respectively, the comprehensive properties of the materials are excellent. The first discharge capacity of 0.1 C is 210 mAh g−1, and the irreversible capacity loss is reduced. Compared with pristine materials, the specific discharge capacity at 5 C was increased by 26 mAh g−1, and the capacity retention rate was improved by 16% after 100 cycles at 1 C. The dual-doping of K and Cl ions can inhibit the mixing of cations, enhance the bond strength between transition metal cations and O2−, and improve the structural stability and the Li+ transport rate. The Al2O3 coating separates the cathode materials from the electrolyte and inhibits the corrosion of the electrolyte to the cathode materials. Therefore, the electrochemical properties of the modified cathode materials are significantly improved. [ABSTRACT FROM AUTHOR]

The influence of the size and oxidation state of Au nanoparticles (AuNPs) as electrocatalysts for the electro-oxidation of cellulose was studied. Carbon paper electrodes modified with AuNPs were used as the electrocatalysts for the electro-oxidation of cellulose dissolved in 1.3 m NaOH. The size and oxidation state of the AuNPs were determined by using SEM, TEM, and X-ray photoelectron spectroscopy. Both the size and the oxidation state of the AuNPs were found to influence the electrocatalytic properties of the electrode, as studied by using cyclic voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy. The carbon paper electrodes decorated with AuNPs (less than 25 nm) that consist of metallic Au gave rise to a significantly higher electrocatalytic activity than a bare polycrystalline Au electrode. [ABSTRACT FROM AUTHOR]

There is a general consensus to develop renewable energy storage and conversion technologies to replace fossil fuel energy for sustainable development. Currently, the development of high performance energy storage and conversion devices is an important step on the road to alternative energy technologies. With a special focus on the upgradation of waste to valuable energy, this paper presents an effective synthetic method that utilizes waste newspapers as the precursor to prepare the activated carbon electrodes by the pyrolysis and chemical activation processes. The amorphous nature and surface morphology of the carbon samples were confirmed by XRD and SEM analysis, respectively. Activated waste newspaper carbon (AWNP) showed good electrochemical properties at 800 °C and its specific capacitance at a scan rate of 2 mV/s was found to be 380 F/g. It is important to mention that the source of the raw material is cost effective and suitable for green technology. [ABSTRACT FROM AUTHOR]

In our previous paper ( Analyst, 2014, 139, 5339) we introduced the concept of the back-to-back electrochemical design where the commonly overlooked back of screen-printed electrodes are utilised to provide electroanalytical enhancements in screen-printed electroanalytical sensors. In this configuration the overall sensor comprises of a flexible polyester substrate which has a total of two working, counter and reference electrodes present on the sensor, with a set of electrodes on each side of the substrate. The sensors are designed to allow for a commonly shared electrical connection to the potentiostat and do not require any specialised connections. In this paper we demonstrate proof-of-concept extending the electroanalytical utility of the back-to-back screen-printed electrode sensors to bulk modified single-walled carbon-nanotubes and electrocatalytic cobalt phthalocyanine microband electrodes. The electroanalytical applications of these novel electrode configuration are exemplified towards the sensing of dopamine, capsaicin and hydrazine. This paper demonstrates the versatility of the back-to-back configuration where different surface modifications can be readily employed giving rise to enhancements in sensor performance. [ABSTRACT FROM AUTHOR]

Urinalysis is attracting interest in personal healthcare management as part of a general move to improve quality of life. Urine contains various metabolites and the protein level in urine is an indicator of kidney function. In this study, a novel electrochemical sensing system based on boron-doped diamond (BDD) electrodes was developed for the detection of protein concentrations in human urine. BDD electrodes have the advantages of a wide electrochemical potential window and low non-specific adsorption, making them ideal for simple, rapid, and compact devices for home detection of bio-relevant substances. Coomassie brilliant blue (CBB), a dye that selectively and strongly binds to urine proteins, was found to be a redox-active indicator to show a decrease in its redox currents in relation to the concentration of protein in urine samples. Our detailed studies of BDD electrodes showed their limit of detection to be 2.57 μg mL−1 and that they have a linear response that ranges from 0 to 400 μg mL−1 in urine samples. We also investigated the detection of urine protein in different urine samples. Our results agreed with those obtained using conventional colorimetric analysis. We believe this to be the first study of electrochemical detection of urine protein in urine samples on BDD electrodes, which is of great significance to be able to obtain results with electrical signals rapidly compared to conventional colorimetric analysis. This CBB–BDD technique has the potential to assist healthcare management in the form of a rapid daily diagnostic test to judge whether a more detailed examination is needed. [ABSTRACT FROM AUTHOR]

The transformation from LiNi1−x−yCoxMnyO2 (NCM) cathodes to Co-free LiNi1−xMnxO2 (NM) cathodes is considered as an effective solution for the electric vehicle (EV) industry to deal with the high cost of cobalt. However, severe Li/Ni disorder, structural instability and poor cycling stability are the main obstacles to their practical application. Al doping has proven to be an effective method to improve the electrochemical performance of Ni-rich NCMs. However, with regard to Ni-rich Co-free NM cathodes, the influence of Al doping on the structural stability and electrochemical performance of NM cathodes is still not clear. In this work, Al doped LiNi0.8Mn0.2−xAlxO2 cathodes are designed and their structural stability and electrochemical performance are investigated by a combination of XRD, SEM, TEM, CV, GITT, cycling testing and EIS techniques. As a result, Al doping can effectively inhibit Li/Ni disorder and improve the structural and thermal stability. In detail, 5% is the optimal doping amount for LiNi0.8Mn0.2O2 cathodes to obtain the best electrochemical performance and the LiNi0.8Mn0.15Al0.05O2 cathode shows an excellent capacity retention of 91.97% after 300 cycles at 3.0–4.3 V. This work provides an effective strategy for the development of Ni-rich Co-free NM cathodes. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) have been considered as promising host frameworks for charge carriers because of their well-defined diffusion channel along the 〈100〉 direction. Among PBA families, Berlin green (BG) would be an ideal cathode platform because the empty carrier ion sites and two redox couples (Fe3+/2+–CN–Fe3+/2+) in the BG framework can deliver high specific capacity during battery operation. Nonetheless, in most solution-based precipitation processes, BG crystals are synthesized in irregular shapes rather than in well-defined cube shapes, thus limiting their capacities at high rate operations. In this work, given the aforementioned challenges, a simple two-step precipitation process to synthesize cubic BG without using any chelating agents and toxic acids was reported. Notably, an intermediate phase was identified as an important stage in converting irregularly shaped BG to cubic BG by releasing crystal water molecules from the framework. Utilizing well-aligned 〈100〉 channels in the cubic framework, cubic BG exhibits excellent electrochemical properties as a cathode for lithium-ion batteries, delivering a specific capacity of 107.2 mA h g−1 at a high current density of 500 mA g−1. A combined study of in situ X-ray diffraction and X-ray absorption fine structure analyses would provide a comprehensive structure–property relationship of BG cathodes. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Advances in the instrumentation and materials for photopolymerization 3D printing aided the use of this powerful technique in the fabrication of microfluidic devices. The costs of printers and supplies have been reduced to the point where this technique becomes attractive for prototyping microfluidic systems with good resolution. With all the development of multi-material 3D printers, most of the microfluidic devices prepared by photopolymerization 3D printing are based on a single substrate material. We developed a digital light processing multi-material 3D printer where two or more resins can be used to prepare complex objects and functional microfluidic devices. The printer is based on a vat inclination system and embedded peristaltic pumps that allow the injection and removal of resins and cleaning step between material changes. Although we have built the whole system, the modification can be incorporated into commercially available printers. Using a high-resolution projector, microfluidic channels as narrow as 43 μm were obtained. We demonstrate the printing of multi-material objects containing flexible, rigid, water-soluble, fluorescent, phosphorescent, and conductive (containing PEDOT or copper nanoparticles) resins. An example of a microfluidic chip containing electrodes for electrochemical detection is also presented. [ABSTRACT FROM AUTHOR]

Layered cathode materials are widely used in conventional lithium-ion batteries with liquid electrolytes. From LiCoO2 (LCO) to Ni-rich (LiNixCoyMnzAl1−x−y−zO2, x ≥ 0.8) materials, different electrochemically active elements bring various properties to the cathodes and therefore they are employed in different fields. Although these layered material systems, composed of different transition metals (TMs), have been intensively studied, their electrochemical properties and interfacial stabilities when paired with promising sulfide solid electrolytes have not been systematically explored. Here, excluding the interference of redundant TMs, we prepared LiNixCo1−xO2 in an attempt to reveal the laws of reactivity at the interface between the layered cathode and the sulfide electrolyte. As a result of systematic analysis, overall, both chemical and electrochemical adverse reactions are proven to be aggravated with the increasing Ni/Co proportion. Compared to that when paired with liquid electrolytes, materials with a high Ni content exhibit much inferior electrochemical stability when paired with sulfide solid electrolytes. The introduction of Co enhances the interfacial stability, whereas the effect becomes less pronounced when the Co content in the system is half or more. This fundamental work deepens the insight into cathode/electrolyte interface deterioration and serves as a guide for designing an appropriate cathode for the up-and-coming all-solid-state lithium batteries (ASSLBs). [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) electrochemical technology is regarded as a very effective industrial wastewater treatment method as it has high treatment efficiency, high current efficiency, and low energy consumption, and especially can completely mineralize nonbiodegradable organic pollutants. The core of the 3D electrochemical technology is a particle electrode, and the particle electrode plays several important roles for removing pollutants during the electrochemical reaction process. Many types of particle electrodes have been developed and used for different types of wastewater treatment. In this paper, a comprehensive review on the research and development of particle electrodes of the 3D electrochemical reactors for wastewater treatment is conducted. Specifically, the role that the particle electrode plays during the 3D electrochemical treatment of wastewater is thoroughly investigated and systematized. In addition, the different types of particle electrodes used in the 3D electrochemical wastewater treatment are classified into several types according to the presence or absence of a catalyst and the main components of the particle electrode or carrier. Also, focusing on the recent research results, the structural characteristics, performance, advantages and defects, and the role of catalyst components of each particle electrodes are evaluated. Finally, the direction and prospect of future research on the particle electrode is presented. [ABSTRACT FROM AUTHOR]

Tattoo electronics is one of the emerging technologies in skin compliant biosensing. The growing interest in their large application in health monitoring raises several interrogations on how these sensors interface with the skin. In this paper, the bioimpedance at the interface of the skin and ultra‐conformable tattoo electrodes made of conducting polymers are focused on. The electrochemical characteristics of these electrodes differ from traditional gelled Ag/AgCl electrodes. The modeling of equivalent circuits in different skin‐electrode configurations proposes the explanation of the biopotentials transduction mechanism. The strong agreement between the circuit model and experimental values reveals the capacitive coupling of conducting polymer tattoo electrodes where circuit's values reflect the electrodes' and skin physical characteristics. Additional studies underline an enhanced signal stability in inter/intra‐subject evaluations using dry tattoos beneficial for broad long‐term recordings. This study provides a comprehensive explanation of the skin/tattoo electrode interface model. The understanding of this interface is essential when designing next generation wearable biomonitoring devices using imperceptible interfaces. [ABSTRACT FROM AUTHOR]

Lightweight, thin, and stretchable flexible microelectronic devices have become a new challenge for researchers. To provide power for these conformable devices, it is necessary to design the energy storage device into a flexible and stretchable structure. In this paper, a two‐step method was used to prepare a dual‐physical cross‐linked polyacrylic acid/chitosan/Ti3C2Tx(PCT) conductive hydrogel flexible electrode. The three‐dimensional (3D) porous structure not only offers a good electrical connection, but also saves the use of binder and additional current collector, which helps to enhance the electrochemical properties of electrode. The unique two‐dimensional layered structure of Ti3C2Tx enables the hydrogel electrode to withstand considerable pressure deformation without breaking, and has excellent tensile properties. The flexible electrode exhibited an excellent tensile strength of 0.083 MPa if only introduced 0.31 wt% of Ti3C2Tx with the tensile strain of 158.63% and owned remarkable self‐healing properties after injury. Thereby, the hydrogel electrode renders a maximum capacitance of 291.8 mF g−1 at 0.5 mA/g and a good cycling stability with 64.24% capacitance retention after 2000 charge–discharge cycles. This provides a research and development strategy for binder‐free, non‐toxic, and mini‐size flexible energy storage devices. [ABSTRACT FROM AUTHOR]

The Bi-mode gate commutated thyristor (BGCT) is a new type of reverse conducting Gate Commutated Thyristor (GCT). This paper focuses on the maximum controllable current capability of BGCTs and proposes new solutions which can increase it. The impact of proposed solutions in the turn-ON and turn-OFF is also assessed. For this analysis, a 2-D mixed mode model for full-wafer device simulations has been developed and utilized. [ABSTRACT FROM PUBLISHER]

Freestanding multiwalled carbon nanotube and titanium (IV) oxide anode paper was prepared by vacuum filtration of multiwall carbon nanotubes/TiO2 hybrid material, which was synthesized by the radio frequency magnetron sputtering techniques. Field emission scanning electron microscopy images revealed that the carbon nanotubes (CNTs) form a three-dimensional nanoporous network, in which ultrafine TiO2 crystals that had crystallite sizes ranging between 7.14 nm and 12.21 nm were distributed homogenously over the surfaces of multiwalled CNT bundles. Electrochemical measurements demonstrated that the prepared powder by using 200 W radio frequency power had excellent cyclic retention, with the high specific capacity of 230 rnAh g−l up to 50 cycles at a current density. Freestanding papers composed of multiwall carbon nanotubes could act as a flexible mechanical support for strain release offering an efficient electrically conducting channel ,whereas the TiO2 provides the high capacity. The electrochemical response is maintained in the initial and further cycling process. Such capabilities demonstrate that this model hold great promise for applications requiring flexible and bendable Li-ion batteries. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper presents the design and development of a trigger with a high repetition rate, low jitter, and compact structure for the pseudospark switch (PSS), which includes an improved Marx generator based on avalanche transistors and a corona-plasma trigger unit. The generator adopted a novel 3 × 12-stage Marx circuit based on avalanche transistors in which the failure rate of transistors in the first and second stages was significantly reduced by connecting the parallel capacitors compared to the previous similar generator. The reason for the improved performance was also discussed. The main parameters of output pulses were an amplitude of −7 kV, rise time of 6 ns, jitter of 0.2 ns, and repetition rate of 2 kHz. The corona-plasma trigger unit adopted BaTiO3 ceramics with high εr as the dielectric and was arranged in the hollow cathode of the PSS. The experiments of triggering a PSS prototype were conducted. The influence of anode voltage and pressure on the trigger delay and jitter was studied, and the minimum trigger jitter achieved <1 ns. This trigger worked for 107 shots at the repetition rate of 2 kHz continuously without obvious performance degradation and any failure of the generator. The main advantage of this trigger is the simultaneous combination of the high repetition rate, low jitter, long lifetime, and great simplicity in a compact structure. [ABSTRACT FROM AUTHOR]

A solid oxide fuel cell (SOFC) with a liquid antimony anode (LAA) is a potential energy conversion technology for the use of impurity-containing fuels. Atmospheric plasma spraying (APS) technology has become a promising LAA-SOFC preparation method because of its economy and convenience. In this paper, button SOFCs with different cathode materials and ratios of pore former were prepared by the APS method and were operated at 750 °C. The effect of the cathode structure on the electrochemical performance of the LAA-SOFCs was analyzed, and an optimized spraying method for LAA-SOFCs was developed. A tubular LAA-SOFC was prepared using the APS method based on the optimized spraying method, and a peak power of 2.5 W was reached. The tubular cell was also measured at a constant current of 2 A for 20 h and was fed with a sulfur-containing fuel to demonstrate its impurity resistance and electrode stability. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries are attracting increasing interest for a new type of green energy battery. Among many electrode materials, layered ternary LiNi1‐x‐yCoxMyO2 (M = Mn or Al) is considered a promising commercial prospect because of its low cost, excellent electrical conductivity, high discharge specific capacity, and environmentally friendly. In this paper, a ternary cathode material LiNi0.8Co0.15Al0.05O2 with high specific capacity was prepared by a two‐step solvothermal method. The effects of solvothermal time and temperature on the morphology and electrochemical properties for the electrode materials were studied. It was found that the electrochemical performance of the LiNi0.8Co0.15Al0.05O2 cathode material synthesized at 180°C for 12 hr was better. [ABSTRACT FROM AUTHOR]

Summary: This paper reports a feasible approach to offer LiNi0.8Co0.1Mn0.1O2 (NCM811) layered cathode materials with enhanced lattice ordering and improved electrochemical performance through a nano grinding assisted solid‐state reaction. Different from the commercial precursor method, oxide raw materials, NiO, CoO and MnO2, rather than the hydroxides, was employed as the starting raw material which was milled into submicron size, pressed into pellets and crushed into granular powder. After calcination under oxygen atmosphere under different temperature, such a simple approach provides layered cathode materials with controllable Li/Ni disordering. Powder XRD results show that when sintered at 800°C, a largest I(003)/I (104) ratio is observed, indicating that the cationic disordering is the lowest, as been confirmed by the XRD refinement data, showing that only 1.08% Ni is misplaced at 3b site. For the electrochemical test, the pNCM800 sample presented an initial specific discharge capacity of 203 mAh/g at 0.1C, together with a capacity retention of 91.77% after 100 cycles at 0.5C. Compared to the value of the sample obtained at normal routine (163.8 mAh/g and 74.85%), the improvement in electrochemical behavior is obvious. Furthermore, the rate performance is also improved, with a specific capacity of 144.1 mAh/g even at 5C rate. The reason for such enhancement could be ascribed to the better kinetic process with low interfacial resistance and fast Li diffusion contributed from the promoted lattice ordering. The results obtained in the experiments greatly indicate the significance of the approach in controlling the Li/Ni disordering, and thus offer an alternative routine for the mass production of layered cathode materials besides the so‐called precursor method. [ABSTRACT FROM AUTHOR]

This paper proposes the use of the boron-doped diamond electrode (BDDE) in flow and batch injection analysis (FIA and BIA) systems with multiple-pulse amperometric (MPA) detection for the determination of warfarin (WA) in pharmaceutical formulations. The electrochemical behavior of WA obtained by cyclic voltammetry (CV) in 0.1 mol L−1 phosphate buffer shows an irreversible oxidation process at +1.0 V ( vs Ag/AgCl). The MPA was based on the application of two sequential potential pulses as a function of time on BDDE: (1) for WA detection at +1.2 V/100 ms and; (2) for electrode surface cleaning at −0.2 V/200 ms. Both hydrodynamic systems (FIA-MPA and BIA-MPA) used for WA determination achieved high precision (with relative standard deviations around 2 %, n=10), wide linear range (2.0−400.0 μmol L−1), low limits of detection (0.5 μmol L−1) and good analytical frequency (94 h−1 for FIA and 130 h−1 for BIA). The WA determination made by the proposed methods was compared to the official spectrophotometric method. The FIA-MPA and BIA-MPA methods are simple and fast, being an attractive option for WA routine analysis in pharmaceutical industries. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel nanomaterial toward (CuCo/CP) electrochemical water splitting. • Facile method for Copper-Cobalt (CuCo) supported on carbon paper (CuCo/CP) composition. • The electrochemical activation of electrode led to improvement of OER and HER kinetics. • Tafel slopes has been calculated for CoCu/CP is 97.7 mV dec−1. • CuCo/CP an emerging material for different energy applications. Electrochemical water splitting is one of the most appealing approaches to produce Hydrogen as a sustainable energy resource. The efficiency of Hydrogen evolution reaction (HER) and Oxygen evolution reaction (OER) largely depends on the activity and stability of any elctrocatalyst. Herein, we have employed a facile and reproducible electrodeposition coating method to synthesize bi-metallic Copper-Cobalt (CuCo) containing electrocatalyst supported on carbon paper (CuCo/CP) for electrochemical splitting of water in neutral medium. We have accomplished superior and improved HER and OER electrocatalytic activity, regardless of lower activity of Cu toward HER and OER. The unique structure and synergistic effect of CuCo/CP displayed better electrocatalytic activity with a low overpotential of 450 mV at 10 mA.cm−2 toward HER and just 80 mV at 10 mA.cm−2 toward Oxygen evolution reaction than other Cu containing electrocatalysts. Moreover, the durability of synthesized electrocatalyst at high applied current density ensure the stable nature of the catalyst. The present study may pave the way for the rational design of electrocatalysts for efficient Oxygen and Hydrogen production applications. [ABSTRACT FROM AUTHOR]

There is an increasing demand for high energy density lithium-ion battery cathodes such as LiNi0.5Co0.2Mn0.3O2 (NCM523); however, severe capacity fading, and structural instability have limited their widespread application. In this study, the effect of surface modification with Li0.33La0.56TiO3 (LLTO) and its crystallinity on the electrochemical performance of NCM523 cathode materials was investigated. Scanning and transmission electron microscopy observation showed a uniform distribution of 3 and 5 wt% LLTO coating, but agglomeration was observed in a higher coating content. According to the electrochemical tests, the amorphous LLTO coating improved the cycling performance and rate capability of the NCM523 cathode. The 5 wt% amorphous LLTO-coated cathode showed the highest discharge capacity after 30 cycles at 0.1 C and after 100 cycles at 0.5 C (136.3 and 104.6 mA h g−1); significantly higher than that of the pristine NCM523 cathode (98.5 and 62.5 mA h g−1). The discharge capacity of this coated sample at 5 C was also much higher than that of the pristine cathode (106.8 compared to 78.5 mA h g−1). In addition, 5 wt% of the amorphous LLTO coating shifted the exothermic peak of the NCM523 electrode from 249 to 281 °C, indicating enhanced safety after the coating process. Compared to the crystalline LLTO-coated NCM523, the cathode with amorphous coating delivered a higher discharge capacity over cycling and at different C-rates. In light of the results, it is evident that surface modification with an amorphous LLTO coating could be a promising approach for industrial application of NCM523 cathode materials. [ABSTRACT FROM AUTHOR]

For obtaining high-performance lithium-ion batteries, it is important to develop new cathode materials with high capacity. Herein, a one-dimensional coordination polymer [Co(4-DTBPT) (DMF)2(H2O)2] (4-DTBPT) (C10H4O8) (Co-DTBPT) (4-DTBPT = 2,7-di(4H-1,2,4-triazol-4yl)benzo[lmn][3,8] phenanthroline-1,3,6,8-(2H,7H)-tetraone; DMF = dimethylformamide) was synthesized and its electrochemical performance as the cathode material of lithium-ion batteries was first investigated. The Co-DTBPT electrode showed better cycling stability and a specific capacity of 55 mA h g−1 at 50 mA g−1 after 50 cycles, and the coulombic efficiency was close to 100%. The capacity contribution of the Co-DTBPT electrode may be ascribed to the redox reaction of the Co(II) ion and the 4-DTBPT ligand in the process of charge and discharge. Our work proves once again that using one-dimensional coordination polymers as cathode materials for lithium-ion batteries is a feasible way. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Solid electrolyte interphases (SEIs) formed on the surface of anode materials are of great importance for high rate and long-life cycling stability. To address this issue, electrolyte additives have been widely used in lithium-ion batteries (LIBs) to modify the electrode–electrolyte interface properties. Herein, vinylene carbonate (VC) has been adopted as an effective additive to form a solid and stable SEI on Li3VO4 (LVO) anodes during cycling. We extensively investigated the fundamental characteristics of the constructed SEI layers and the related electrochemical reaction kinetics involved in the LIB environment. It was found that the introduction of VC into electrolytes could apparently enhance the rate capability and significantly improve the long-term cycling performance of Li3VO4 anodes. The obtained LVO in the electrolyte with the addition of VC exhibits a high reversible capacity of 810.4 mA h g−1, high rate performance of 521.2 mA h g−1 at 5.0 A g−1 and excellent cycling stability with 82.9% capacity retention for 2000 cycles at 10.0 A g−1. This work demonstrates that the formation of an appropriate SEI on the surface of LVO is necessary for the improvement of the electrochemical performance. [ABSTRACT FROM AUTHOR]

Li-rich antiperovskite (Li2Fe)SO with its high specific capacity is an attractive cathode material for Li-ion battery applications. While many battery materials depend on hazardous substances and their production is also rarely sustainable, we present an environmentally friendly and sustainable approach for the synthesis of Li-rich (Li2Fe)SO using mechanochemistry based on ball milling. This one step process enables preparing a large quantity of phase-pure (Li2Fe)SO using low-cost and non-toxic precursors, making it a viable alternative to current solid state synthetic method in terms of simplicity, laboratory safety and scalability. The obtained micro-sized particles are nearly spherical and have a small size distribution. To control the crystallinity and reduce the intrinsic defects of the ball-milled (Li2Fe)SO material, a post-heat treatment procedure was tested. Thermodynamic measurements confirmed the high thermal stability of the ball-milled (Li2Fe)SO material. Increasing the ball to powder weight ratio was found to be an effective strategy to decrease the milling time required for the synthesis, thus promoting energy saving. Overall, this work provides a practical guide for the green and scalable production of (Li2Fe)SO cathode material, as well as a method for particle modification for improved electrochemical properties. [ABSTRACT FROM AUTHOR]

The uniform coating of catalytic materials on the electrode surface is essential for improving the performance of electrochemical reactions. In this study, the electrostatic spray coating technique is used to deposit Molybdenum disulfide (MoS 2) particles on carbon electrodes and examine the electrochemical hydrogen evolution reaction (HER) performance in a 0.1 M H 2 SO 4 electrolyte. The experimental results reveal that the electrostatic spray coating method achieves a more uniform coating MoS 2 catalyst particles on the carbon fiber substrate. It provides good adhesion for electrocatalyst binding on the carbon paper electrodes. During HER analysis, a 25% higher current density is obtained from the electrostatic spray-coated electrodes compared to the manual spray-coated electrode at a potential of 0.95 V. Electrochemical impedance spectroscopy, and electrochemical surface area measurements indicate the superior electrochemical characteristics of the electrostatic spray-coated electrode. The faradaic efficiency of the electrostatic spray-coated electrode is close to 100% at a high applied potential of −1.6 V with a 0.0059 L volume of hydrogen generation. Moreover, chronoamperometric measurements demonstrate the excellent durability of the electrostatic spray-coated carbon electrodes. This study suggests that the facile electrostatic spray method is efficient for coating electrodes with high uniformity and good adhesion for various electrochemical applications. • The parametric study and its results verify the relevant coating method for HER process. • The electrostatic spray is the efficient method, exhibits high uniformity and good adhesion. • The electrostatic spray-coated electrodes delivered higher current density than manual spray-coated electrodes. • The electrostatic spray provides 100% faradaic efficiency at −1.6 V. [ABSTRACT FROM AUTHOR]

Currently, the preparation of high-performance electrode materials is urgently needed for supercapacitors. As a new kind of organic porous material, covalent organic frameworks (COFs) with an ordered pore structure, a high specific surface area and designability, have shown great potential application value as electrode materials for supercapacitors. However, their potential application in supercapacitors is limited by the poor conductivity of COFs. Here, we in situ grew the highly crystalline triazine-based covalent organic framework DHTA-COF on a modified -Al2O3 substrate to obtain the composites Al2O3@DHTA-COFs. Some of the obtained Al2O3@DHTA-COF composites can maintain some degree of crystallinity, good stability and a vesicular structure. Compared to the precursors -Al2O3 and DHTA-COF, the 50%Al2O3@DHTA-COF composite has superior electrochemical properties as electrode materials for supercapacitors. Under the same conditions, the specific capacitance values of 50%Al2O3@DHTA-COF (261.5 F g−1 at 0.5 A g−1) are 6.2 and 9.6 times higher than the values of DHTA-COF and -Al2O3–CHO, respectively. Additionally, the 50%Al2O3@DHTA-COF electrode material exhibited long-term cycling stability even after 6000 charge–discharge cycles. The study can provide some reference for the development of COF-based composite materials for energy storage. [ABSTRACT FROM AUTHOR]

Energy storage devices (ESDs) need designing and development of high electrochemical performance and promising electrode materials. Transition-metal chalcogenides (TMCs) are being actively investigated as the electrode for electrochemical ESDs. Herein, we report the design, synthesis, and electrochemical properties of the MnSe electrode by a facile hydrothermal method. The as-synthesized MnSe electrode has a flower-like morphology with the planes growing perpendicular to its center. The results of electrochemical performance testing indicate that the pseudocapacitive nature of the MnSe electrode has a critical effect on those properties. The MnSe electrode exhibits a specific capacitance of 423.1 F g−1 at a current density of 1 A g−1 and better cyclic stability among 3000 cycles. The synthesis of MnSe electrodes opens up opportunities for the design of TMCs electrode materials and the development of supercapacitors. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries have attracted great research attention because of their high energy density and low cost. However, shuttling effects of polysulfides and insulation from elemental sulfur hinder their practical application. Herein, we report hollow carbon nanofibers filled with carbon nanotubes (denoted as HCNF/CNT) as host materials for sulfur to mitigate the shuttling behavior and improve the kinetics of insulative sulfur. The as-prepared HCNF/CNT with nano-conductive domains in the hollow carbon nanofibers enables high loading and efficient utilization of sulfur. Owing to their unique structural superiority, the sulfur-encapsulated HCNF/CNT cathode materials for Li–S batteries deliver excellent electrochemical performance, including high specific capacity of 1156 mA h g−1 at 0.2 C, good rate performance and cycling stability with a capacity retention of 77.2% after 200 cycles at 2 C. Such a unique structure can provide inspiration for the rational structural design of carbon materials as hosts for high performance Li–S batteries. [ABSTRACT FROM AUTHOR]

For the first time, silver nanoparticles (AgNPs) were fabricated with graphite pencil electrode (GPE) by immersing a bare hard black pencil (HB pencil) in AgNO3 solution mixed with extract Quercus infectoria solution, followed by placing directly against to UV lamp (254 nm) and kept for 30 min. Silver modified-GPEs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometer (EDX). The silver nanoparticles fabricated with graphite pencil electrode (AgNPs-GPE) showed excellent selectivity to chloride ion, as well as excellent reproducibility, together with it has several advantages such as sensitivity, simplicity, low cost, green, and fast response. The maximum oxidation cyclic voltammogram current of the AgNPs-PGE was found at 160 mV. The linear range of chloride ions detection is between (0.8-52 mmol L-1), and the limit of detection (LOD) of chloride ions is 0.041 mmol L-1. Finally, the Silver fabrication electrode was used to determine the chloride ion concentration in drugs, such as phenylephrine, metformin, procaine, and dopamine formulated with hydrochloride, and satisfactory results were obtained. [ABSTRACT FROM AUTHOR]

In this paper, 9,10-anthraquinone (AQ) derivative-modified glassy carbon (GC) electrodes were studied towards the electrochemical reduction of oxygen in aqueous and non-aqueous solutions. The reaction of 1-chloro-9,10-anthraquinone with aliphatic diamines was applied for the synthesis of amino-9,10-anthraquinone derivatives. The obtained AQ derivatives were grafted onto the surface of glassy carbon electrodes by electropolymerisation using diazonium salts. The modified GC electrodes are sensitive to oxygen, determined by cyclic voltammetry. Changes in the oxygen determination efficiency depend mostly on the length of the side chain AQ derivative which is grafted to the GC electrode and is nearly double in comparison to a bare GC electrode modified by 1-((2-((2-aminoethyl)amino)ethyl)amino)-9,10-anthraquinone. [ABSTRACT FROM AUTHOR]

This study reports a new electrochemical method for tryptamine determination using a paper-based microfluidic device and a thermoplastic electrode (TPE) as an amperometric detector. Tryptamine (Tryp) is a biogenic amine present in drinks and foods. Even though this compound has some beneficial effects on human health, the ingestion of foods with high concentrations of Tryp may be detrimental, which justifies the need for monitoring the Tryp levels. The TPEs were made from 50% carbon black and 50% polycaprolactone and characterized by cyclic voltammetry, demonstrating enhancement in the analytical response compared to other carbon composites. TPEs also showed a better antifouling effect for Tryp compared to conventional glassy carbon electrodes. Once characterized, the electrodes were incorporated into the microfluidic device to determine Tryp in water and cheese samples using amperometry. A linear range was achieved from 10 to 75 μmol L−1 with limits of detection and quantification of 3.2 and 10.5 μmol L−1, respectively. Therefore, this work shows promising findings of the electrochemical determination of Tryp, bringing valuable results regarding the electrochemical properties of thermoplastic composites. Image 1 • Fouling resistant thermoplastic electrodes (TPEs) for tryptamine determination. • 50% carbon black and 50% polycaprolactone were used to prepare the electrodes. • TPE-μPAD can ensure fast analyses and generate less waste. • Possibility of reusing the electrodes by simply polishing them after several uses. • A simple strategy to eliminate ascorbic acid interference. [ABSTRACT FROM AUTHOR]

In the paper, the Zr4+ and F− co-doping was employed to expectedly improve the rate performance and structure stability of Li1.20[Mn0.54Ni0.13Co0.13]O2. The effects of Zr4+ doping and F− doping on the micro-structure, cathode morphology and element chemical state were investigated by XRD, Rietveld refined XRD, SEM, TEM, and XPS. It indicated the Zr4+ and F− were inserted into the cathode crystal structure with ideally designed. Besides, the electrochemical characterization confirmed that the cathode after the Zr4+ or/and F− doping delivered the superior electrochemical properties when compared to the pristine one. Firstly, the Li1.20[Mn0.52Ni0.13Co0.13Zr0.02]O1.95F0.05 could express a high discharge capacity of 132.6 mAhg−1 at 5C rate, which was 40.1 mAhg−1 larger than that of the pristine one (92.5 mAhg−1). In addition, the Li1.20[Mn0.52Ni0.13Co0.13Zr0.02]O1.95F0.05 remained a capacity retention of 90.7% after 100 cycles at 2C rate and with the 148.2 mAh g−1 left. While the bare cathode delivered an initial discharge capacity of 134.1 mAhg−1 at 2C rate, then dramatically attenuated to 108.7 mAhg−1 after 100 cycles with the capacity retention of 81.1%. The enhanced electrochemical properties of Li1.20[Mn0.52Ni0.13Co0.13Zr0.02]O1.95F0.05 was mainly put down to the suppression of charge transfer resistance increase by the Zr4+ and F− doping modification along with cycles. [ABSTRACT FROM AUTHOR]

Surface modification has been one of most effective methods to improve the electrochemical performance of lithium rich layered oxides. In this paper, the Li1.2Mn0.56Ni0.16Co0.08O2 microspheres are prepared by urea assisted combustion route, and then coated with proper amount of CaF2. XRD and SEM results show surface modification has not changed the structure of Li1.2Mn0.56Ni0.16Co0.08O2, and a uniform coating layer can be obtained. As lithium ion battery cathode, the optimal CaF2 (i.e, 2 wt.%) coated sample presents a high initial discharge capacity of 223 mAh·g-1 with Coulombic efficiency of 80.5 % at 0.1 C, which is much better than that of pristine sample. Also, a high discharge capacity of 119 mAh·g-1 can be obtained for CaF2 coated sample at 5 C. The improved electrochemical performance may be attributed the formation of fast Li ion conductor on the surface supported by EIS study. [ABSTRACT FROM AUTHOR]

Ni‐rich cathode materials have become one of the most promising cathode materials for advanced high‐energy Li‐ion batteries (LIBs) owing to their high specific capacity. However, Ni‐rich cathode materials are sensitive to the trace H2O and CO2 in the air, and tend to react with them to generate LiOH and Li2CO3 at the particle surface region (named residual lithium compounds, labeled as RLCs). The RLCs will deteriorate the comprehensive performances of Ni‐rich cathode materials and make trouble in the subsequent manufacturing process of electrode, including causing low initial coulombic efficiency and poor storage property, bringing about potential safety hazards, and gelatinizing the electrode slurry. Therefore, it is of considerable significance to remove the RLCs. Researchers have done a lot of work on the corresponding field, such as exploring the formation mechanism and elimination methods. This paper investigates the origin of the surface residual lithium compounds on Ni‐rich cathode materials, analyzes their adverse effects on the performance and the subsequent electrode production process, and summarizes various kinds of feasible methods for removing the RLCs. Finally, we propose a new research direction of eliminating the lithium residuals after comparing and summing up the above. We hope this work can provide a reference for alleviating the adverse effects of residual lithium compounds for Ni‐rich cathode materials' industrial production. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries suffer from mechano–electrochemical coupling problems that directly determine the battery life. In this paper, we investigate the electrode electrochemical performance under stress conditions, where seven tensile/compressive stresses are designed and loaded on electrodes, thereby decoupling mechanics and electrochemistry through incremental stress loads. Four types of multi-group electrochemical tests under tensile/compressive stress loading and normal package loading are performed to quantitatively characterize the effects of tensile stress and compressive stress on cycle performance and the kinetic performance of a silicon composite electrode. Experiments show that a tensile stress improves the electrochemical performance of a silicon composite electrode, exhibiting increased specific capacity and capacity retention rate, reduced energy dissipation rate and impedances, enhanced reactivity, accelerated ion/electron migration and diffusion, and reduced polarization. Contrarily, a compressive stress has the opposite effect, inhibiting the electrochemical performance. The stress effect is nonlinear, and a more obvious suppression via compressive stress is observed than an enhancement via tensile stress. For example, a tensile stress of 675 kPa increases diffusion coefficient by 32.5%, while a compressive stress reduces it by 35%. Based on the experimental results, the stress regulation mechanism is analyzed. Tensile stress loads increase the pores of the electrode material microstructure, providing more deformation spaces and ion/electron transport channels. This relieves contact compressive stress, strengthens diffusion/reaction, and reduces the degree of damage and energy dissipation. Thus, the essence of stress enhancement is that it improves and optimizes diffusion, reaction and stress in the microstructure of electrode material as well as their interactions via physical morphology. [ABSTRACT FROM AUTHOR]

Transition‐Metal chalcogenides have high Li‐ion storage capacity and considerable cycle performance, which has attracted great interest from researchers and is expected to replace graphite materials in the field of Li ion batteries. The purpose of this paper is to find a low‐cost and ecofriendly method for producing copper‐based chalcogenides as anodes with a high capacity and long cycling stability for lithium ion batteries. In our strategy, carbon nanospheres are used as templates to prepare precursor Cu(OH)2@C. Then, the Cu(OH)2@C is converted into copper‐based chalcogenides by different routes. The structure and morphology of the as‐synthesized materials is characterized by the X‐ray diffraction, scanning electron microscopy and transmission electron microscopy. The anode electrochemical performance of the samples was investigated by galvanostatic cycling (GC) vs. Li/Li+ at different current rate. Compared to other copper chalcogenides, the synthesized copper oxide shows better charge/discharge cycle stability and rate performance. Its capacity retention is as high as 128 % at a current density of 0.5 C after 200 cycles. [ABSTRACT FROM AUTHOR]

The ternary‐layered oxide (LiNixCoyMnzO2) has become the most promising cathode material for lithium‐ion batteries due to the advantages of higher discharge platform, better conductivity, and higher theoretical capacity. The [NixCoyMnz](OH)2 with different ratios of nickel, cobalt, and manganese (NCM) was prepared by solvothermal method, and then ternary cathode material LiNixCoyMnzO2 was obtained by mixing lithium and calcining. In this paper, ternary cathode materials with different ratios of NCM were prepared by the solvothermal method. The structure and morphology of the materials were analyzed by X‐ray diffraction, scanning electron microscopy, and energy‐dispersive spectroscopy. The effects of the ratio on the electrochemical properties of the materials were investigated by constant current charge and discharge test and electrochemical impedance spectroscopy test. The synthesized lithium‐nickel‐cobalt‐manganese oxide belongs to the hexagonal system and has an α‐NaFeO2 layered structure, which is an R‐3m space group. The NCM ternary cathode materials with different morphologies were obtained by changing the ratio of NCM. The sample with NCM ratio of 5:3:2 has a unique sheet‐like spherical shape and has the best rate performance. [ABSTRACT FROM AUTHOR]

In this paper, the Ni 1. 5 Co 1. 5 S4@CNTs nanocomposites containing different carbon nanotubes (CNT) content were prepared by a one-step hydrothermal method. More hydroxyl and carboxyl groups were introduced on the surface of CNTs by acidizing treatment to increase the dispersion of CNTs. The acid-treated CNTs can more fully compound with Ni 1. 5 Co 1. 5 S4 nanoparticles to form heterostructure. When the CNTs content is 10 wt.%, the Ni 1. 5 Co 1. 5 S4@CNTs-10 nanocomposite exhibits the highest specific capacity of 210 mAh g − 1 in KOH aqueous electrolytes at current density of 1 A g − 1 . The superior performances of the Ni 1. 5 Co 1. 5 S4@CNTs-10 nanocomposite are attributed to the effective synergic effects of the high specific capacity of Ni 1. 5 Co 1. 5 S4 and the excellent conductivity of CNTs. An asymmetric supercapacitor (ASC) was assembled based on Ni 1. 5 Co 1. 5 S4@CNTs-10 positive electrode and activated carbon (AC) negative electrode, which delivers a high energy density of 61.2 Wh kg − 1 at a power density of 800 W kg − 1 , and maintains 34.8 Wh kg − 1 at a power density of 16079 W kg − 1 . Also, the ASC device shows an excellent cycling stability with 91.49% capacity retention and above 94% Columbic efficiency after 10 000 cycles at 10 A g − 1 . This aqueous asymmetric Ni 1. 5 Co 1. 5 S4@CNTs//AC supercapacitor is promising for practical applications due to its advantages such as high energy density, power delivery and cycling stability. The Ni1.5Co1.5S4@CNTs nanocomposites have been prepared by a hydrothermal route. The Ni1.5Co1.5S4@CNTs nanocomposite with 10 wt.% CNTs shows a high specific capacity owing to maximizing synergic effects of high specific capacity of the Ni-Co metal sulfide and excellent conductivity of CNTs. A supercapacitor based on the Ni1.5Co1.5S4@CNTs nanocomposite is promising for practical applications due to its high energy density, high power delivery and low cost. [ABSTRACT FROM AUTHOR]

The cathode plasma jets in vacuum arc and the effect of magnetic field on them have been studied for several years and these studies are helpful to understand the arc characteristics and improve the controlling effect of magnetic field on arc plasma. In this paper, the experiments of the cup-shaped axial magnetic field (AMF) contacts were conducted in which a Helmholtz coil was introduced to generate different external imposed AMFs. It was found that the appearance of arc plasma was changed by variation of the external imposed AMF. If the composite AMF in arc column increased gradually, the obvious individual cathode plasma jets were detected, the arc constriction decreased, and the arc stability increased. Meanwhile, the inclination of cathode plasma jets was observed and the inclination direction was found to be consistent with the magnetic field vector direction which is closely related to the composite AMF. By variation of the external imposed AMF and its direction, the inclination direction of cathode plasma jets also changed. The criterion to detect obvious cathode jets in arc column is obtained that at the contact peripheral where R> 80.5% R0 (R0 is the contact radius), the AMF strength is no less than 4.5 mT/kA. It was also found that if the composite AMF in interelectrode gap points to different directions at a certain moment, it may lead to the transfer of arc column from the center to the edge of the interelectrode region and the arc instability until when the composite AMF in the interelectrode gap points to the same direction. It can be concluded that the appearance of individual cathode plasma jets can be manipulated by the variation of AMF, which is helpful to study the interaction between arc plasma and electrodes, especially the anode, and improve the interruption performance at higher current. [ABSTRACT FROM PUBLISHER]

We examined the laser-induced discharge (LID) in medium-vacuum air. The time-averaged discharge energy Wd of a primary discharge prior to an arc discharge was affected by the number of initial electrons. The initial electrons were produced by the laser irradiation of electrodes. The number of electrons was proportional to the energy of the laser, Lp. Thus, it was adjusted by changing Lp. Although the experimental conditions were rather limited, i.e., air at 200-Pa pressure, we demonstrated a simple relationship, \textWd\propto \,\,\text{V}s^{2} \times \,\,\text{L}p^{s} , where Vs is the applied voltage and s is an exponent determined empirically. Note that the number of initial electrons is a function of Lp. Such a simple relationship for the behavior of LID that incorporates Wd is proposed for the first time in this paper. [ABSTRACT FROM AUTHOR]