Electrode Shape Research Articles

An Advanced Microstructural and Electrochemical Datasheet on 18650 Li-Ion Batteries with Nickel-Rich NMC811 Cathodes and Graphite-Silicon Anodes

Cylindrical lithium-ion batteries are used across a wide range of applications from spacesuits to automotive vehicles. Specifically, many manufacturers are producing cells in the 18650 geometry i.e., a steel cylinder of diameter and length ca. 18 and 65 mm, respectively. One example is the LG Chem INR18650 MJ1 (nominal values: 3.5 Ah, 3.6 V, 12.6 Wh). This article describes the electrochemical performance and microstructural assembly of such cells, where all the under-pinning data is made openly available for the benefit of the wider community. The charge-discharge capacity is reported for 400 operational cycles via the manufacturer’s guidelines along with full-cell, individual electrode coating and particle 3D imaging. Within the electrochemical data, the distinction between protocol transition, beginning-of-life (BoL) capacity loss, and prolonged degradation is outlined and, subsequently, each aspect of the microstructural characterization is broken down into key metrics that may aid in understanding such degradation (e.g., electrode assembly layers, coating thickness, areal loading, particle size and shape). All key information is summarized in a quick-access advanced datasheet in order to provide an initial baseline of information to guide research paths, inform experiments and aid computational modellers.

Simulation Guided Microfluidic Design for Multitarget Separation Using Dielectrophoretic Principle

Microfluidic technologies have emerged as a potential tool for point of care — diagnostics and therapeutics applications. Isolation of multi-targets (Cancer cells along with platelets, red blood cells (RBCs), white blood cells (WBCs), and antigen-presenting cells (APCs)) simultaneously is of great interest in drug discovery and medical diagnosis. By utilizing dielectrophoresis (DEP) effect inside the micro channel, several attempts were made to separate binary mixtures by precisely controlling and manipulating the motion of the particles. However, all of these methods limit its applicability for multi-target particle separation in a single run. In this paper, we attempt to develop a simulation model with novel electrode arrangements to isolate multiple particles using negative DEP. Our proposed model establishes criteria for separating micron-sized particle mixtures (3µm, 7µm, 15µm, 20µm, 25µm) with various electrode shapes, electrode potentials, inlet velocities, and channel widths. The device efficiency was evaluated for a triangular electrode, square-shaped electrode, and rectangular electrode under various practical design constraints. Our study demonstrates an optimum solution for effective separation of particle mixtures using triangular electrode arrangements (utilizing less voltage) and a wider channel of 300µm width that eventually avoid channel clogging issues due to cells inside main channel and collection channels. While evaluating the separation efficiency of the proposed design, we observe that platelets, RBCs, WBCs, APCs, and CTCs experienced distinct DEP force on each, allowing them to collect in different collection outlets without any cross-mixing. Hence our proposed design allows flexibility to the researchers working on DEP by using a wider channel with triangular electrode arrangements enabling them to fabricate the device under resource-limited constraints.

Enhanced Desalination Performance of Capacitive Deionization Using Nanoporous Carbon Derived from ZIF-67 Metal Organic Frameworks and CNTs.

Capacitive deionization (CDI) based on ion electrosorption has recently emerged as a promising desalination technology due to its low energy consumption and environmental friendliness compared to conventional purification technologies. Carbon-based materials, including activated carbon (AC), carbon aerogel, carbon cloth, and carbon fiber, have been mostly used in CDI electrodes due their high surface area, electrochemical stability, and abundance. However, the low electrical conductivity and non-regular pore shape and size distribution of carbon-based electrodes limits the maximization of the salt removal performance of a CDI desalination system using such electrodes. Metal-organic frameworks (MOFs) are novel porous materials with periodic three-dimensional structures consisting of metal center and organic ligands. MOFs have received substantial attention due to their high surface area, adjustable pore size, periodical unsaturated pores of metal center, and high thermal and chemical stabilities. In this study, we have synthesized ZIF-67 using CNTs as a substrate to fully utilize the unique advantages of both MOF and nanocarbon materials. Such synthesis of ZIF-67 carbon nanostructures was confirmed by TEM, SEM, and XRD. The results showed that the 3D-connected ZIF-67 nanostructures bridging by CNTs were successfully prepared. We applied this nanostructured ZIF-67@CNT to CDI electrodes for desalination. We found that the salt removal performance was significantly enhanced by 88% for 30% ZIF-67@CNTs-included electrodes as compared with pristine AC electrodes. This increase in salt removal behavior was analyzed by electrochemical analysis such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements, and the results indicate reduced electrical impedance and enhanced electrode capacitance in the presence of ZIF-67@CNTs.

Optimization of pipe-and-spike discharge electrode shape for improving electrostatic precipitator collection efficiency

Numerical analysis was conducted to investigate the effect of wire length, spacing between wires, and wire bending angle, which are geometric parameters of a pipe-and-spike discharge electrode, on collection efficiency. Discharge electrode shape was optimized using the Near Orthogonal Array method. When the distance between collecting plates and the number of discharge electrode wires were fixed, a longer wire length and greater distance between the wires increased the collection efficiency, which was the highest when the bending angle of the wire was 160°. Numerical results were validated through experiments. Collection efficiency of the electrostatic precipitator was increased by about 15% by the optimized discharge electrode, and power consumption and ozone generation showed little difference after optimization. Based on the results of this study, the optimization of the shape of various discharge electrodes is expected to effectively improve the collection efficiency of various types of electrostatic precipitators.

Investigation of a Liquid-Phase Electrode for Micro-Electro-Discharge Machining.

Micro-electro-discharge machining (μEDM) plays a significant role in miniaturization. Complex electrode manufacturing and a high wear ratio are bottlenecks for μEDM and seriously restrict the manufacturing of microcomponents. To solve the electrode problems in traditional EDM, a µEDM method using liquid metal as the machining electrode was developed. Briefly, a liquid-metal tip was suspended at the end of a capillary nozzle and used as the discharge electrode for sparking the workpiece and removing workpiece material. During discharge, the liquid electrode was continuously supplied to the nozzle to eliminate the effects of liquid consumption on the erosion process. The forming process of a liquid-metal electrode tip and the influence of an applied external pressure and electric field on the electrode shape were theoretically analyzed. The effects of external pressure and electric field on the material removal rate (MRR), liquid-metal consumption rate (LMCR), and groove width were experimentally analyzed. Simulation results showed that the external pressure and electric field had a large influence on the electrode shape. Experimental results showed that the geometry and shape of the liquid-metal electrode could be controlled and constrained; furthermore, liquid consumption could be well compensated, which was very suitable for µEDM.

Byproducts Generation Characteristics of Non-thermal Plasma for NO Conversion: Effect of Reaction Conditions

Over the years, the combined Non-thermal Plasma (NTP) denitrification process which is used for decomposition of NOx has have become an application technology with great potential. And the formation of byproducts, such as N2O and O3, which is an important factor that interfere with NO removal efficiency, has a high research value. In present study, HZSM-5 molecular sieve was selected as the packed material in dielectric barrier discharge reactor to investigate the effect of reaction conditions, such as with/without packed bed, discharge power, inner electrode diameter, electrode shape and operation time, on formation and conversion characteristics of byproducts (N2O and O3). Results showed that the presence of HZSM-5 pellets in discharge zone increases the discharge power, NO removal efficiency and the concentration of the byproducts in the outlet. The optimization of electrode diameter and the utilization of screw thread electrode increased the NO removal efficiency and the yield of N2O and O3. The pellets temperature increases with the operation time and the enhancement of input energy, which has different effects on O3 and N2O. These results provide some new methods for improving the NTP-assisted catalytic denitrification process.

Developing a versatile electrochemical platform with optimized electrode configuration through screen-printing technology toward glucose detection.

Rapid on-site detection of glucose has been attracting considerable attention nowadays. Screen-printed electrodes (SPEs) were assessed as ideal detection platforms due to their advantages such as, disposability, portability, ease of miniaturization, and mass production. The topology and shape of electrodes have a crucial impact on their electrical conductivity and electrochemical properties. In this study, a versatile electrochemical platform with optimized three-electrode configuration was developed through screen-printing technology. Three types of SPEs were prepared, and their electrocatalytic properties toward glucose detection were investigated. Based on this platform, both enzyme-based (denoted as GOD/rGO) and non-enzymatic (denoted as Co@MoS2/rGO) bioactive compounds were deposited on the working electrode of the circular SPE through simply drop-casting, respectively. Their morphology was characterized through scanning electron microscopy (SEM). Cycle sweep voltammetry was used to study the electrocatalytic activity of these biosensors. The circular SPE exhibited satisfying electrochemical redox activity and much higher sensitivity towards glucose detection, which rendered it a promising candidate for point-of-care detection.

Features of the Electrophoretic Formation of Bulk Compacts Based on Zirconium Oxide Nanopowder

The possibility of forming bulk compacts via electrophoretic deposition (EPD) using a nanopowder based on yttria-stabilized zirconia (YSZ) is considered. Features of the kinetics of mass growth and changes in cell resistance and the morphology of the sediment during a long deposition time are studied using different geometries of the counter electrode of the EPD cell (flat and conical). EPD is performed with a stepwise increase in electric field strength. It is found that the shape of the counter electrode does not appreciably affect either the kinetics of changes in current or the growth of cell resistance, or the fraction of the solid phase in the wet compact in a suspension with sufficiently low conductivity (∼22.2 μS/m). Slight increases of 8–10% in the mass of wet and dry compacts and 10.5% in the electric current are observed when a conical form of the counter electrode is used instead of a flat one. Numerical modeling is done in a two-dimensional approximation, allowing determination of the effect the counter electrode’s geometry has on the local distribution of the electric potential and current density near the electrode.

Multi-component plasma fluid approach to sparking enhanced burns as a complication of diathermy

Background: The effects of electric currents flowing through a human body vary from no perceptible to severe tissue injury caused by the electrosurgical spark. Although modern electrodes have been designed to minimize this complication, it was reported that burns have accounted for 70% of the injuries during electro surgery. Some risks of complications depend on a surgeon's knowledge of instruments and safety aspects of technical equipment. The use of alcohol and spirit-based skin preparation solutions brings another risk of burn injuries.Methods: Apart from the experimental methods, computer modelling is shown to be an effective approach to improve the performance of electrosurgical procedure. The benefits of simulation assisted electro surgery include no ethical approval, low cost, safe and the most important removing conditions that may lead to tissue burns. Here, the onset of sparking between the electrosurgical electrodes has been studied by using the multi-component plasma fluid model. Results: It was found that the electrode shape significantly affects the sparking formation. The minimum voltage required for sparking has been achieved for cylinder-cylinder configuration, while for other arrangements breakdown voltages are higher. Electrical sparks do not occur equally in both directions between active and passive electrodes due to electrical asymmetries.Conclusions: This study is dealing with application of multi-component plasma fluid model in simulating sparks produced between electrosurgical electrodes of various shapes, materials and dimensions. Our simulation model offers substantially greater physical fidelity as compared to simulators that use simple geometry. The obtained results are applicable for prevention of potential complications during diathermy procedure.

Engineering Aspheric Liquid Crystal Lenses by Using the Transmission Electrode Technique

The transmission electrode technique has been recently proposed as a versatile method to obtain various types of liquid-crystal (LC) lenses. In this work, an equivalent electric circuit and new analytical expressions based on this technique are developed. In addition, novel electrode shapes are proposed in order to generate different phase profiles. The analytical expressions depend on manufacturing parameters that have been optimized by using the least squares method. Thanks to the proposed design equations and the associated optimization, the feasibility of engineering any kind of aspheric LC lenses is demonstrated, which is key to obtain aberration-free lenses. The results are compared to numerical simulations validating the proposed equations. This novel technique, in combination with the proposed design equations, opens a new path for the design and fabrication of LC lenses and even other types of adaptive-focus lenses based on voltage control.

Investigating the Electrical Properties of Different Cochlear Implants.

Aim:This study characterises and compares electrical properties and current spread across four different makes of cochlear implants with differing electrode designs using a 3D-printed artificial cochlear model.Background:Cochlear implants are currently limited by current spread within the cochlea, which causes low spectral resolution of auditory nerve stimulation. Different cochlear implant makes vary in electrode size, shape, number, and configuration. How these differences affect cochlear implant current spread and function is not well known.Method:Each cochlear implant was inserted into a linear cochlear model containing recording electrodes along its length. Biphasic monopolar stimulation of each implant electrode was carried out, and the resultant waveform and transimpedance matrix (TIM) data obtained from the recording electrodes. This was repeated with each implant rotated 180 degrees in the cochlea model to examine the effects of electrode orientation. Impedance spectroscopy was also carried out at the apex, middle, and base of the model.Results:The four cochlear implants displayed similar TIM profiles and waveforms. One hundred eighty degrees rotation of each cochlear implant made little difference to the TIM profiles. Impedance spectroscopy demonstrated broad similarities in amplitude and phase across the implants, but exhibited differences in certain electrical parameters.Conclusion:Implants with different designs demonstrate similar electrical performance, regardless of electrode size and spacing or electrode array dimension. In addition, rotatory maneuvers during cochlear implantation surgery are unlikely to change implant impedance properties.

Accurately Mapping Image Charge and Calibrating Ion Velocity in Charge Detection Mass Spectrometry.

Image charge detection is the foundation of charge detection mass spectrometry (CDMS). The mass-to-charge ratio, m/z, of a highly charged ion or particle is determined by measuring the particle's charge and velocity. Charge is typically determined from a calibrated image charge signal, and the particle velocity is calculated using the peaks from the shaped signal as they relate to the particle position and time-of-flight through a detector of known length. Although much has been done to improve the charge accuracy in CDMS, little has been done to address the inconsistencies in the particle velocity measurements and the interpretation of peak position and effective electrode length. In this work, we combine SIMION ion trajectory software and the Shockley-Ramo theorem to accurately determine the effective electrode length, peak position, and shape of the signal peaks. Six model charge detector geometries were examined with this method and evaluated in laboratory experiments. Experimental results in all cases agreed with the simulations. Using a charge detector with multiple, 12.7 mm-long cylindrical electrodes, experimental velocities across and between electrodes agreed within 0.25% relative standard deviation (RSD) when this method was used to correct for effective electrode lengths, corresponding to an uncertainty in the effective electrode length of only 40 μm. For a detector with multiple electrodes and varied electrode spacing, experiments showed that the peak amplitude and shape vary with the geometry and with the particle path through the detector, whereas all peak areas agreed to within 2.3% RSD. For a charge detector made of two printed circuit boards, the velocities agreed within 0.44% RSD using the calculated effective electrode length.

Investigation on turning operation using die sinking EDM process

Electrical discharge turning (EDT) operation produces a cylindrical component using an electrical discharge machining method. Unlike a traditional turning process, it is a non-contact operation between the tool electrode and workpiece. Therefore, the design of electrode may influence the quality of turned workpiece. The present study investigates the effect of various processing parameters in EDT namely the electrode shape, workpiece rotational speed and jump down time. The analysis was conducted in terms of the surface roughness, circularity deviation and electrode wear rate. A special jig and fixture for the turning operation was developed as to fit on the commercial die sinking EDM machine. A fractional factorial approach using Taguchi orthogonal array of L9 was utilized in the present study. It was found that both shape of electrode and workpiece rotational speed had a greater influence on the surface roughness followed by the electrode jump down time. The surface roughness increases with an increase of quantity and duration of sparks during the process due to formation of a higher amount of debris. The circularity deviation has improved with a higher sparking area and faster duration of sparks since a smaller amount of workpiece material was removed thus improving its circularity. Furthermore, the highest electrode wear rate was produced using the electrode with a curvature shape which generated wider sparking area thus experiencing more erosion.

Electro‐oxidation of phenol in petroleum wastewater using a novel pilot‐scale electrochemical cell with graphite and stainless‐steel electrodes

AbstractThis work investigated the removal of phenol from petroleum wastewater by the electro‐oxidation process. The experimental design was developed on a pilot‐scale electro‐oxidation system equipped with a cylindrical shape of graphite electrodes as an anode and stainless‐steel electrodes as a cathode. An initial study was performed based on operating variables such as current density and time on real petroleum wastewater. The optimum conditions were obtained as a current density of 3 mA/cm2 and time 15 min. Under these applied optimum conditions, complete phenol removal from an initial concentration of about 6.8 mg/L was achieved. Also, 50–60% removal of organic matter in terms of chemical oxygen demand (COD) and biological oxygen demand (BOD). The removal of organic matter using electro‐oxidation requires a long reaction time. Also, the economic study indicated that the energy consumption was determined to be 0.79 kWh/m3 and the operating cost was 0.051 $/m3 which is very economical compared with conventional methods.

Micro arc discharge surface treatment on BO1 steel

The abrasive wear resistance of BO1 steel is significantly improved when treated with the micro arc process. After treatment both the material bulk properties and dimensions of the treated samples (with the exception of the surface roughness) were unchanged. Parameters such as electrode stand-off distances, oil film thickness, and electrode shape, greatly influences the final characteristics of the surface. Meticulously polishing the substrate surface before treatment lead to a uniform distribution of hard carbides on the treated surfaces. Samples treated for short duration display better wear resistance due to their smoother surfaces. However, those treated for longer durations have very hard carbides that extend far deeper into the surface. This is a desirable characteristic for tools subject to combined abrasive and erosive wear.

Deposition and patterning of electrodes on the vertical sidewalls of deep trenches

A process able to produce at wafer scale patterned electrodes on the vertical sidewalls of trenches is described and investigated in detail. It is based on metal evaporation at oblique incidence through a shadow mask made in a dry photoresist film. A full model of the deposition and patterning process is established in order to map the shape as well as the thickness and density of patterned electrodes with or without wafer rotation. In the case of wafer rotation, the modelling is based on the analogy of each shadow mask edge with the gnomon of a sundial. The final electrode shape is then computed from the trajectories followed by the shadows of the gnomons. Offset of the substrate tilt axis with respect to substrate plane, and position on the wafer surface, are considered in the analysis, as well as the variation of film density with incidence angle. Advantages and limitations of the proposed process are discussed. It is shown that sidewall electrodes isolated or connected to top or bottom electrodes can be simply achieved by a suitable sizing and alignment of the shadow mask but that close electrodes on a given sidewall cannot be mutually isolated when the substrate is rotated. The patterning process is demonstrated in the case of Au/Cr electrodes on the sidewalls of through wafer trenches made in GaAs by deep reactive ion etching.

Uniformization of Mass Sensitivity Distribution of Silver Electrode QCM.

Quartz crystal microbalance (QCM) is a highly sensitive mass sensor and has been widely used in many fields. However, the nonuniform distribution of mass sensitivity will lead to poor reproducibility of QCM, which is not conducive to the application of QCM in some fields. Considering the effect of electrode shape, size, and material on mass sensitivity distribution, we found that for an AT-cut QCM with a fundamental frequency of 10 MHz, when the inner and outer diameters of silver ring electrode and the electrode loading factor are 2 and 5 mm and 0.0033, respectively, an approximately uniform mass sensitivity distribution can be obtained. The plating experiment in which rigid silver films were plated on the surface of electrode verified the uniformity. The uniform mass sensitivity distribution will make the application of QCM more convenient; the reproducibility can also be improved. This design of QCM will enrich QCM products and facilitate the application of QCM in various fields.

Tuning the type of charge carriers in N-heterocyclic carbene-based molecular junctions through electrodes* *Project supported by the National Natural Science Foundation of China (Grants Nos. 11874242 and 21933002) and the Shandong Provincial Natural Science Foundation, China (Grant No. ZR2019PA022).

Designing tunable molecular devices with different charge carriers in single-molecule junctions is crucial to the next-generation electronic technology. Recently, it has been demonstrated that the type of charge carriers depends on and can be tuned by controlling the molecular length and the number of interfacial covalent bonds. In this study, we show that the type of charge carriers can also be tuned by controlling the material and shape of electrodes. N-heterocyclic carbenes (NHCs) have attracted attention because of their ability to form strong, substitutional inert bonds in a variety of metals. Also, NHCs are more stable than the widely used thiol group. Therefore, we use electrodes to tune the type of charge carriers in a series of NHCs with different side groups. The ab initio calculations based on non-equilibrium Green’s formalism combined with density functional theory show that the dominant charge carrier switches from electrons to holes when gold electrodes are changed into platinum ones. The nature of the charge carriers can be identified by variations in the transport spectra at the Fermi level (E F), which are caused by the side groups. The projections of transport spectra onto the central molecules further validate our inferences. In addition, the transmission coefficient at E F is found to be dependent on the atomic interface structure. In particular, for the NHC without methyl or ethyl side groups, connecting a protruding atom on the electrode surface significantly enhances the transportability of both electrode materials. Overall, this study presents an effective approach to modifying transport properties, which has potential applications in designing functional molecular devices based on NHCs.

Betavoltaic battery based on reduced-Graphene-Oxide/Si heterojunction

Abstract This paper presents a new beta converter cell based on reduced graphene oxide (rGO)/Si heterojunction suitable for betavoltaic batteries. The potential barrier created in the rGO/Si interface induces an internal electric field in the Si substrate. This internal electric field can be used for separating the beta-generated electron-hole pairs in Si. Ni63, with the activity of 5mci is used as the beta radioisotope source. The current-voltage characteristic of the cell is measured with and without radioisotope radiations. The circuit model of the junction is also presented. The cell shows an open circuit voltage of 34 mV, a short circuit current of 0.41 μA/cm2, and high conversion efficiency of 3.9% under exposure of beta radioisotope Ni63. The presented structure, additionally, benefits from the capability of graphene in the absorption of beta particles and carrier separation via ununiformed finger shape of front electrodes.

Design of an Open Electrowetting on Dielectric Device Based on Printed Circuit Board by Using a Parafilm M

In recent years, the open electrowetting on dielectric (EWOD) device has been widely used in biomedical detection, chemical synthesis analysis, and so on. However, the cost of using ITO glass as surface material is difficult to meet the requirement for large-scale array chip production. So, a low-cost, easy-to-manufacture open EWOD platform is designed in this paper. In hardware platform, an operation platform is prepared by using a printed circuit board (PCB) as a substrate. The electrode shape is designed as zigzag, and its surface is optimized by organic solderability preservatives (OSP). In addition, Parafilm M and silicone oil are used as a dielectric hydrophobic layer to prepare the open platform. In software, the system program is designed by C programming language, including initialization program, serial port communication program, high-voltage output port program, and interrupt program, which can be used to drive droplets. The system can achieve an effective driving voltage of 180V-240V. The moving speed of droplets can reach 15mm/s when the droplet volume is 18μL-50μL and the electrode voltage output frequency is 10Hz.