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Lithium-ion batteries are available in three primary configurations: cylindrical, prismatic, and pouch cells. The distinct shapes of these formats introduce variations in electrochemical performance and mechanical response. This study extensively investigates the influence of cell format on electrochemical and mechanical responses, expanding investigations with higher C -rates and next-generation battery materials exhibiting significantly larger expansion ratios. To the best of our knowledge, no simulation studies on large-scale cell format comparisons comprehensively considering the electrochemical and mechanical responses of the electrode design currently exist, especially for high expansion ratio materials. A physics-based 2D model integrating particles, electrodes, and cell levels was employed to achieve this, unraveling the interplay between mechanical and electrochemical reactions. Although stress improved electrochemical performance, the impact of geometric differences appeared minimal. However, significant volume expansion reduces the electrochemical performance and highlights format-driven variations, with pouch cells demonstrating superior electrochemical performance, followed by prismatic and cylindrical cells at 1C. The stress and strain patterns mimicked the concentration distributions, while the circular regions introduced uneven stress and deformation. Therefore, ensuring cell safety requires thicker separators in high-strain circular areas. This study presents a safe cell design, encompassing considerations of electrochemical and mechanical responses in current lithium-ion batteries and next-generation technologies. • Investigated electrochemical and mechanical responses across different cell formats. • Considered higher C -rates and higher expansion ratio materials. • Explored how distinct shapes impact voltage, concentration, stress/strain patterns. • Proposed a safer cell design, especially in high-strain circular regions. [ABSTRACT FROM AUTHOR]

Electrochemical impedance spectroscopy is an important tool for fuel-cell analysis and monitoring. This study focuses on the low-AC frequencies (2–0.1 Hz) to show that the thickness of the catalyst layer significantly influences the overall resistance of the cell. By combining known models, a new equivalent circuit model was generated. The new model is able to simulate the impedance signal in the complete frequency spectrum of 105–10−2 Hz, usually used in experimental work on polymer electrolyte fuel cells (PEMFCs). The model was compared with experimental data and to an older model from the literature for verification. The electrochemical impedance spectra recorded on different MEAs with cathode catalyst layer thicknesses of approx. 5 and 12 µm show the appearance of a third semicircle in the low-frequency region that scales with current density. It has been shown that the ohmic resistance contribution (Rmt) of this third semicircle increases with the catalyst layer’s thickness. Furthermore, the electrolyte resistance is shown to decrease with increasing catalyst-layer thickness. The cause of this phenomenon was identified to be increased water retention by thicker catalyst layers.

Electrocatalytic nitrogen reduction reaction (eNRR) is a promising method for sustainable ammonia production. Although the majority of studies on the eNRR are devoted to developing efficient electrocatalysts, it is critical to study the influence of mass transfer because of the poor N 2 transfer efficiency. Herein, a novel bubble-based microreactor (BBMR) is proposed that efficiently promotes the mass transfer behavior during the eNRR using microfluidic strategies. The BBMR possesses abundant triphasic interfaces and provides spatial confinement and accurate potential control, ensuring rapid mass transfer dynamics and improved eNRR performance, as confirmed by experimental and simulation studies. The ammonia yield of the reaction over Ag nanoparticles can be enhanced to 31.35 µg h -1  mg cat. , which is twice that of the H-cell. Excellent improvements are also achieved using Ru/C and Fe/g-CN catalysts, with 5.0 and 8.5 times increase in ammonia yield, respectively. This work further demonstrates the significant effect of mass transfer on the eNRR performance and provides an effective strategy for process enhancement through electrode design.-1 , which is twice that of the H-cell. Excellent improvements are also achieved using Ru/C and Fe/g-CN catalysts, with 5.0 and 8.5 times increase in ammonia yield, respectively. This work further demonstrates the significant effect of mass transfer on the eNRR performance and provides an effective strategy for process enhancement through electrode design., (© 2023 Wiley‐VCH GmbH.)

The synchronized development of low cost, high energy density, full‐scale lithium‐ion battery (LIB) vehicle/truck storages with long charge/discharge cycles, long‐term stability, and excellent rate capacity and Coulombic efficiency is crucial. Here, structurally folded curvature surface cathode/anode models were designated as vehicle/truck storages. The modulation of LIB vehicle folds with diverse surface functions such as cave‐in‐hollow nests, shell‐walled/fenced edges, and convex/concave spheroid‐capped gradients of geode (G)/agate rosette (AR) (cathode/anode) electrodes may be used as leverage to motivate the dynamic mobility of electron‐ion motion systems directly and generate vehicle/truck storage loading on sustainable electrode surface geometrics, leading to long‐term charge/discharge cycles. In this vehicle/truck storage design, evidence of the effect of structurally folded curvature surface models on the creation of anode/cathode designs is first reported as the force‐driven modulation of high energy density of full‐scale G‐cathode//AR‐anode LIBs. The built‐in LIB is formulated with structurally shaped spheroids along whole‐, eroded‐, and unopened G‐cathodes and AR‐anodes that exhibit the effect of the remarkable surface curvature function changes on fabrication of well‐defined geometric LIBs. The building design of G‐cathode//AR‐anode LIBs with a bundle of convex/concave spheroid‐capped gradients, and three‐dimensional (3D) surface curvatures offer a massive gate‐in transport of electrons/Li+ ions for long periods of charge/discharge cycles and outstanding discharge capacities. Outstanding long‐term cycling performance and stability, excellent retention capacity ∼85 % with a first discharge specific capacity of 162.5 mAh g−1 and an approximate Coulombic efficiency of 99.7 %, were obtained after 2000 cycles at a rate of 1 C in a potential region from 0.8 V to 3.5 V versus Li/Li+ at room temperature by using 3D super‐scalable G@C//AR@C built‐in full‐scale LIB models. A high value of specific energy density ≈131.6 Wh kg−1. The full‐scale LIB models may offer all mandatory requirements overcoming the energy density limits that required a driving range of long‐term EVs. [ABSTRACT FROM AUTHOR]

• A novel electrode set is assessed for enhancing the electrocoalescence. • The geometry is ladder and V-shaped, and the electrodes are bare. • Both droplet–droplet and droplet–interface coalescence are promoted in this design. • Pulsatile DC fields are more effective in promoting coalescence than constant ones. • Optimum values of electrical parameters exist for the fluid physical properties. Electrocoalescence is an energy-efficient and environmentally-friendly process for breaking water-in-oil emulsions. It has been used extensively in the oil and petroleum industries. However, the current technology requires long residence times, giving rise to bulky vessels for industrial scale operations and making it less attractive for offshore application. It is also highly desirable to develop compact devices for down-the-well use. In this study, the performance of a novel electrode geometry, a ladder-shaped set of electrodes through which the emulsion flows, is assessed for enhancing the electrocoalescence, hence providing the potential for a compact design. The electrodes are formed into a V shape, with the apex pointing towards the direction of flow. This configuration enables nesting a series of electrodes in a compact form. Furthermore, the water-in-oil emulsion flows through the electrodes rather than passing by them, thus maximizing the effect of the electric field for coalescence. The system under study uses dispersed water droplets in sunflower oil, flowing in a narrow rectangular duct through the electrodes, providing essentially a two-dimensional flowing stream. The performance of this design is investigated for different electrical parameters (i.e. electric field intensity, frequency and waveform), fluid physical properties (i.e. conductivity and water content) and residence time. Of the three types of electric field waveform (i.e. half-sinusoidal, square and sawtooth), sawtooth performs best at high conductivities. Experiments reveal the existence of optimal values of electric field intensity, electric field frequency, salt concentration and water concentration, where the coalescence efficiency is maximum for the current design. Numerical simulation of the electrocoalescence process is conducted to assess the influence of various geometric and process parameters on the coalescence mechanisms of the V-shape electrodes. The outcome of this work is potentially useful for optimizing the design of compact and efficient oil–water separators. [ABSTRACT FROM AUTHOR]

Commercial lithium ion cells are now optimised for either high energy density or high power density. There is a trade in cell design between the power and energy requirements. A tear down protocol has been developed, to investigate the internal components and cell engineering of nine cylindrical cells, with different power-energy ratios. The cells designed for high power applications used smaller particles of the active material in both the anodes and the cathodes. The cathodes for high power cells had higher porosities, but a similar trend was not observed for the anodes. In terms of cell design, the coat weights and areal capacities were lower for high power cells. The tag arrangements were the same in eight out of nine cells, with tags at each end of the anode, and one tag on the cathode. The thicknesses of the current collectors and separators were based on the best (thinnest) materials available when the cells were designed, rather than materials optimised for power or energy. To obtain high power, the resistance of each component is reduced as low as possible, and the lithium ion diffusion path lengths are minimised. This information illustrates the significant evolution of materials and components in lithium ion cells in recent years, and gives insight into designing higher power cells in the future. [ABSTRACT FROM AUTHOR]

We consider basic and easily extendible transport formulations for lithium batteries consisting of an anode (Li-foil), a separator (polymer electrolyte), and a composite cathode (composed of electrolyte and intercalation particles). Our mathematical investigations show the following novel features: (i) complete and very basic description of mixed transport processes relying on a neutral, binary symmetric electrolyte resulting in a non-standard Poisson equation for the electric potential together with interstitial diffusion approximated by classical diffusion; (ii) upscaled and basic composite cathode equations allowing to take geometric and material features of electrodes into account ; (iii) the derived effective macroscopic model can be numerically solved with well-known numerical strategies for homogeneous domains and hence does not require to solve a high-dimensional numerical problem or to depend on computationally involved multiscale discretization strategies where highly heterogeneous and realistic, nonlinear, and reactive boundary conditions are still unexplored. We believe that the here proposed basic and easily extendible formulations will serve as a basic and simple setup towards a systematic theoretical and experimental understanding of complex electrochemical systems and their optimization, e.g. Li-batteries. [ABSTRACT FROM AUTHOR]

The 3-D finite-element model (FEM) of a Y-cut plano-plano langasite crystal thickness shear mode (TSM) resonator is presented, and Mindlin’s theory is used to investigate the optimal electrode shapes and sizes for langasite crystal resonator. Circular and elliptical electrodes of various arc lengths are studied to identify the most optimal electrode design configuration in order to achieve TSM vibration free from any anharmonic modes. Simulation results show that resonators with elliptical electrodes have noticeably better suppression of spurious modes compared to that of circular electrodes. Moreover, spurious mode suppression is accomplished for multiple electrode sizes for the same shape, which greatly differs from Mindlin’s theory. Hence, three optimized designs are shortlisted and their mass loading sensitivities are investigated. Circular and elliptical electrodes of the same area show similar responses to added mass, indicating that elliptical electrodes have no apparent advantage over circular electrode in mass sensing applications. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs), as a class of typical two‐dimensional materials, have sparked increasing interest in the field of energy storage and conversion. In the last few years, the research about LDHs as electrode active materials has seen much progress in terms of structure designing, material synthesis, properties tailoring, and applications. In this review, we focus on the integrated nanostructural electrodes (INEs) construction using LDH materials, including pristine LDH‐INEs, hybrid LDH‐INEs, and LDH derivative‐INEs, as well as the performance advantages and applications of LDH‐INEs. Moreover, in the final section, the insights about challenges and prospective in this promising research field were concluded, especially in regulation of intrinsic activity and uncovering of structure–activity relationship, which would push forward the development of this fast‐growing field. [ABSTRACT FROM AUTHOR]

Abstract This work aimed at evaluating the effects of high-voltage electric field (HVEF) produced by an improved electrode system on the freezing behaviors and selected properties of agarose gel. The freezing of the agarose gel was realized by a Peltier cooler coupled with an improved electrode system. The electrode system was integrated with a dielectric spacer having high permittivity to avoid partial discharges. Results showed that HVEF combined with a low freezing rate significantly reduced the supercooling degree, enhanced the average freezing rate in particular the nucleation rate, and higher internal electric field intensity showed a better microstructure with smaller ice crystals in frozen samples. Under the highest applied voltage of 9 kV ( E i n = 1.09 E+05 V/m) tested in this study, a 100% supercooling release was achieved. Maximum reductions of 78.83%, 25.79% and 28.75% were observed for the nucleation time, tempering time and total freezing time, respectively, while the phase transition time was prolonged by 14.86% as compared with the control (p < 0.05). Some reinforcement was detected in the gel strength by increasing internal electric field intensity, but not significant enough to prevent the structural damage and syneresis caused by freezing and thawing. This study suggested that HVEF-assisted freezing was able to reduce the size of ice crystals formed in semi-solid model foods, and the integration of a dielectric spacer with high permittivity to the electrode could be used as a potential method to solve the electrical discharge problem. Highlights • An improved electrostatic freezing (EF) system was developed. • Electrodes with dielectric spacer could strengthen the internal field intensity. • EF reduced supercooling degree and enhanced freezing rate. • EF enhanced gel strength but did not prevent freezing damage. • EF reduced the size of ice crystals formed in agarose gel. [ABSTRACT FROM AUTHOR]

Potassium‐Oxygen (K−O2) batteries have a high theoretical energy density of 935 Wh kg−1 due to a single‐electron redox process in the reversible formation of potassium superoxide. Despite this advantage, standard K−O2 batteries have limited cycle‐life (5‐10) due to molecular oxygen crossover from cathode to anode, resulting in side reactions forming undesired superoxide on the anode. In this article, a K−O2 battery fabricated with a functionally‐graded cathode (FGC) architecture is presented to address oxygen crossover at the cathode. This K−O2 battery lasts >125 cycles with minimal loss in coulombic efficiency when charged/discharged to 300 μAh (238 μAh cm−2). The FGC is comprised of a carbon fiber layer, microporous carbon and polypyrrole doped with hexafluorophosphate. It provides a scalable architecture for regulating K+ ion and oxygen transport at the cathode trilayer (liquid‐solid‐air) interface. The PPy(PF6) formed on the cathode is observed to have an ORR rate two orders greater than that of carbon‐based electrodes, as it promotes the reversible formation of potassium superoxide at the cathode, minimizes the transport of molecular oxygen into the electrolyte, and subsequently improves anode stability and cycle‐life of the K−O2 battery. These improvements in performance with FGC come at a marginal increase in K−O2 battery material cost, which is estimated to be $44 kWh−1. The combination of performance and cost kWh−1 makes this architecture the most cost‐effective electrochemical energy storage device for stationary applications. [ABSTRACT FROM AUTHOR]

In the orbital mode of electrical discharge machining (EDM), an electrode with a complex profile causes deviation in the cavity profile from the design objective. In this paper, electrode compensation techniques according to the envelope theory are presented to eliminate deviation errors. The succession of orbits traced out a family of electrode curves based on kinematic geometry integrated with the motion path of tool bodies and constraints. The boundary of the family of electrode curves is referred to as the orbiting profile. The deviation error between the orbiting and objective profiles can be eliminated by using a compensation electrode in the orbiting process. Thus, the generated orbiting profile conforms to the objective profile. Experimental results of the tested example for the machining profile of the compensation electrode by using the orbital process revealed that profile deviation can be eliminated to ensure that the EDM profile closely conforms to the objective profile. This compensation method for orbiting EDM provided an exact process to engineers for easy control of the machining precision of EDM. [ABSTRACT FROM AUTHOR]

Atmospheric ice accretion is considered a severe safety issue for technical systems such as communication infrastructure, power lines, blades of wind turbines, and so on in cold climate regions. Among different sensing systems to detect and provide reliable information about the state of ice, capacitive sensing has been reported as a suitable technique. In capacitive sensing, measured capacitances are influenced due to ice accretion. Signal processing for ice sensors requires to estimate parameters for the state of ice from the data. In this paper, we present a model-based estimation approach for capacitive ice sensors. We analyze different electrode topologies for ice sensing and provide a statistical analysis of the sensor behavior. We hereby consider the random nature of natural ice accretion. From simulations, we show how a statistical model for the measurement process can be derived and demonstrate the construction of estimation algorithms within the Bayesian framework. We will demonstrate the capability of our approach for automated ice detection by means of long-term field data showing the ability to estimate ice layers with a precision better than 1 mm. [ABSTRACT FROM AUTHOR]

Abstract The targeted optimization of Li-ion batteries (LIBs) requires a fundamental understanding of the wide variety of interdependencies between electrode design and electrochemical performance. In the present study, the effects of thickness and porosity on the electrochemical performance and Li-ion insertion kinetics of LiNi 0.6 Co 0.2 Mn 0.2 O 2 -based (NCM-622) cathodes are investigated. Cathodes of different thickness and porosity are prepared and analyzed regarding their rate capability. The polarization behavior is investigated using electrochemical impedance spectroscopy. A simple mathematical model is employed to estimate the impact of Li-ion diffusion limitations in the electrolyte. The results are considered at both, the materials and the full-cell level. The design parameters are found to have distinct impact on the electrolyte, contact and charge transfer resistance as well as the Li-ion diffusion limitations in the electrolyte, significantly influencing the rate capability. The results attest an inherent tradeoff between energy and power density. The insights of this study can be used straightforward for the optimization of gravimetric and volumetric energy density of LIBs depending on the desired application. Graphical abstract Image 1 Highlights • The impact of electrode thickness and porosity of NCM-622 cathodes is analyzed. • The design parameters affect energy and power density of the electrode. • A low porosity benefits electronic but impedes ionic transport properties. • For thick electrodes, Li-ion diffusion in the electrolyte becomes rate limiting. • Trade-off between energy and power density related to the design parameters. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Influence factors for CDI performance in carbon and Faradaic electrodes are stressed. • Material design principles of high-performance CDI electrode are emphasized. • Emerging porous carbons and intercalating electrode materials are overviewed. • Relationship of structure/functionality vs resultant CDI performance is elucidated. Abstract Capacitive deionization is an energy-saving and environmental friendly water treatment technique with cost advantage especially for salt water with low/medium concentration. Upon sophisticated structure design and functionality regulation, novel derived carbon materials with optimized hierarchical pore structure and well-tailored surface characteristics and Faradaic materials with unique ion intercalation effects have exhibited enhanced salt adsorption capacity, high removal rate, increased ion selectivity and excellent long-term cycling stability, showing great potential in expanding CDI technique to the practical application in treatment of real waters with different salinity and complex compositions. Despite the great progress, there is absent of a review that emphasizes the design strategies of such materials from the point of view of structure/functionality-CDI property relationship and provides insight into the key factors in designing CDI electrode materials with enhanced performance. Herein, the effect and mechanism of pore structure and surface characteristics on the desalination performance of carbon electrode materials is firstly elucidated. Correspondingly, the Faradaic nature of intercalating materials in improving the salt removal performance is introduced. The design principles of carbon and intercalating CDI electrode for better deionization are summarized. Secondly, recent progresses in high-performance carbon electrode materials derived from graphene, metal-organic frameworks and biomass are introduced based on varied synthetic methods, relationship connecting the rational pore structure and functionalization is emphasized. Thirdly, the materials development and cell design of intercalating electrodes for improved desalination performance is highlighted. At last, the opportunities and development directions in CDI electrode materials are overviewed. [ABSTRACT FROM AUTHOR]

Lithium metal batteries have achieved large-scale application, but still have limitations such as poor safety performance and high cost, and limited lithium resources limit the production of lithium batteries. The construction of these devices is also hampered by limited lithium supplies. Therefore, it is particularly important to find alternative metals for lithium replacement. Sodium has the properties of rich in content, low cost and ability to provide high voltage, which makes it an ideal substitute for lithium. Sulfur-based materials have attributes of high energy density, high theoretical specific capacity and are easily oxidized. They may be used as cathodes matched with sodium anodes to form a sodium-sulfur battery. Traditional sodium-sulfur batteries are used at a temperature of about 300 °C. In order to solve problems associated with flammability, explosiveness and energy loss caused by high-temperature use conditions, most research is now focused on the development of room temperature sodium-sulfur batteries. Regardless of safety performance or energy storage performance, room temperature sodium-sulfur batteries have great potential as next-generation secondary batteries. This article summarizes the working principle and existing problems for room temperature sodium-sulfur battery, and summarizes the methods necessary to solve key scientific problems to improve the comprehensive energy storage performance of sodium-sulfur battery from four aspects: cathode, anode, electrolyte and separator.

As most of the light and easy oil fields have been produced or are nearing their end-life, the emulsion stability is enhanced and water cut is increasing in produced fluid which have brought challenges to oil–water separation in onshore and offshore production trains. The conventional solution to these challenges includes a combination of higher chemical dosages, larger vessels and more separation stages, which often demands increased energy consumption, higher operating costs and larger space for the production facility. It is not always feasible to address the issues by conventional means, especially for the separation process on offshore platforms. Electrostatic coalescence is an effective method to achieve demulsification and accelerate the oil–water separation process. In this paper, a novel compact electrostatic coalescer with helical electrodes was developed and its performance on treatment of water-in-oil emulsions was investigated by experiments. Focused beam reflectance measurement (FBRM) was used to make real-time online measurements of water droplet sizes in the emulsion. The average water droplet diameters and number of droplets within a certain size range are set as indicators for evaluating the effect of coalescence. We investigated the effect of electric field strength, frequency, water content and fluid velocity on the performance of coalescence. The experimental results showed that increasing the electric field strength could obviously contribute to the growth of small water droplets and coalescence. The extreme value of electric field strength achieved in the high-frequency electric field was much higher than that in the power-frequency (50 Hz) electric field, which can better promote the growth of water droplets. The initial average diameters of water droplets increase with higher water content. The rate of increment in the electric field was also increased. Its performance was compared with that of the plate electrodes to further verify the advantages of enhancing electrostatic coalescence and demulsification with helical electrodes. The research results can provide guidance for the optimization and performance improvement of a compact electrocoalescer.

As a promising large-scale energy storage device, the vanadium redox flow battery (VRFB) has attracted attention due to its excellent safety, the independence between energy capacity and power capacity, the suitable polarization potential, and the ability to avoid cross-contamination. In this work, a 3D model of VRFB is developed based on the open-source computational fluid dynamics (CFD) platform OpenFOAM, which is well-validated. Then, the effect of operating conditions is studied, which shows that a higher electrolyte concentration can reduce the overpotential and increase the discharge voltage. Reducing the current density can increase the deepness of charge and discharge, reduce the electrolyte concentration gradient, the mass transfer loss and the activation loss. In addition, the effect of electrode porosity is studied that the overpotential decreases near the membrane and increases near the current collector with increasing porosity. Finally, the effect of porosity changes in different directions is studied, and an attempt is made to utilize this overpotential distribution by introducing the gradient-porosity electrode to reduce the non-uniformity of overpotential. The gradient-porosity electrode design using higher porosity near the membrane and lower porosity near the current collector can effectively improve the distribution of overpotential and increase battery performance by 1.67 mV. [Display omitted] • A VRFB model is developed under open-source environment OpenFOAM. • The effect of electrolyte concentration and current density is studied. • The overpotential distribution pattern caused by different porosity is summarized. • The performance with the gradient-porosity electrode is increased by 1.67 mV. [ABSTRACT FROM AUTHOR]

Traditional capacitive electrocardiogram (cECG) electrodes suffer from limited patient comfort, difficulty of disinfection and low signal-to-noise ratio in addition to the challenge of integrating them in wearables. A novel hybrid flexible cECG electrode was developed that offers high versatility in the integration method, is well suited for large-scale manufacturing, is easy to disinfect in clinical settings and exhibits better performance over a comparable rigid contactless electrode. The novel flexible electrode meets the frequency requirement for clinically important QRS complex detection (0.67–5 Hz) and its performance is improved over rigid contactless electrode across all measured metrics as it maintains lower cut-off frequency, higher source capacitance and higher pass-band gain when characterized over a wide spectrum of patient morphologies. The results presented in this article suggest that the novel flexible electrode could be used in a medical device for cECG acquisition and medical diagnosis. The novel design proves also to be less sensitive to motion than a reference rigid electrode. We therefore anticipate it can represent an important step towards improving the repeatability of cECG methods while requiring less post-processing. This would help making cECG a viable method for remote cardiac health monitoring.

Summary: Lithium‐sulfur batteries have attracted much research interest because of their high theoretical energy density and low‐cost raw materials. While the electrodes are composed of readily available materials, the processes that occur within the cell are complex, and the electrochemical performance of these batteries is very sensitive to a number of cell processing parameters. Herein, a simple electrochemical model will be used to predict, with quantitative agreement, the electrochemical properties of lithium‐sulfur cathodes with varying carbon to sulfur ratios. The discharge capacity and the polarization were very similar for the lowest sulfur loadings, while above 23.2 wt% sulfur the gravimetric capacity dropped significantly, and there was an increase in the cell polarization. In addition, a transition in the electrode morphology, from well dispersed to aggregated sulfur at the surface, will be reflected in the change in a critical model parameter demonstrating the sensitivity and functionality of even this simple model in predicting complex behavior in the lithium‐sulfur cells. Lithium‐sulfur batteries are very promising as a next‐generation high‐energy density battery system, and improvements in understanding and designing these batteries will help to accelerate their development. This study was a combined experimental and computational efforts where complex cell behavior in lithium‐sulfur cells was captured using a one‐dimensional model. In particular, the polarization as a function of the carbon to sulfur ratio and transitions in polarization due to agglomeration of sulfur in the electrode will be described. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride (PVDF) piezoelectric nanofibers were fabricated through near-field electrospinning (NFES) to develop a flexible piezoelectric element. Innovative screen printing technology was employed to produce bend-type electrodes designed with d33 mode patterns. The electrodes and PVDF nanofibers were then attached to a polyimide film substrate. Compared with piezoelectric ceramics, piezoelectric fibers are inexpensive, flexible, and highly biocompatible. They also have a higher electron density than piezoelectric films, indicating that they are more efficient in electromechanical conversion. Thus, in this study, we adopted piezoelectric fibers to create a displacement sensor with bend-type electrodes that employed optimized pattern designs to increase the efficiency of piezoelectric conversion and sensitivity. The experimental results revealed that the type of electrode was critical for enhancing output voltage. The novel bend-type electrodes induced an average positive voltage of 960.5 mV during a tapping experiment, increasing the maximum voltage by 59.74% compared with a series-type electrode. The positioning accuracy of the displacement sensor was 600 µm; thus, the sensor could successfully determine positioning, confirming the feasibility of the displacement sensing mechanism. [ABSTRACT FROM AUTHOR]

Objective: The ideal form of a neural-interfacing device is highly dependent upon the anatomy of the region with which it is meant to interface. Multiple-electrode arrays provide a system that can be adapted to various neural geometries. Computational models of stimulating systems have proven useful for evaluating electrode placement and stimulation protocols, but have yet to be adequately adapted to the unique features of the hippocampus. Methods: As an approach to understanding potential memory restorative devices, an admittance method-NEURON model was constructed to predict the direct and synaptic response of a region of the rat dentate gyrus to electrical stimulation of the perforant path. Results: A validation of estimated local field potentials against experimental recordings is performed and results of a bilinear electrode placement and stimulation amplitude parameter search are presented. Conclusion: The parametric analysis presented herein suggests that stimulating electrodes placed between the lateral and medial perforant path, near the crest of the dentate gyrus, yield a larger relative population response to given stimuli. Significance: Beyond deepening understanding of the hippocampal tissue system, establishment of this model provides a method to evaluate candidate stimulating devices and protocols. [ABSTRACT FROM AUTHOR]

Single ion conductors, such as solid electrolytes are promising alternatives to overcome drawbacks of lithium-ion batteries with binary electrolytes, e.g. thermal runaway and electrolyte decomposition. Within this research a pseudo-two-dimensional (P2D) battery model for cells with single ion conducting electrolytes is derived and compared to a state of the art P2D model for cells with binary electrolytes to elucidate the theoretical differences in cell performance when replacing binary with single ion conducting electrolytes, as well as the related advantages and bottlenecks. At high discharge rates, electrolyte potential losses are more distinct for binary electrolytes compared to single ion conducting electrolytes which results in a higher energy for the latter one. Further, sensitivity to variations in electrode and electrolyte are elucidated analyzing discharge curves, Electrochemical Impedance Spectroscopy (EIS) and maximal energy. Parameter variations indicate that single ion conducting electrolyte cells allow thick electrode designs. They can therefore be advantageous to classical binary electrolyte cells when building high energy cells, once the high conductivities of laboratory studies found their way into application. [ABSTRACT FROM AUTHOR]

A hybrid Zn battery is developed by integrating a Zn-Co 3 O 4 battery and a Zn-air battery at the cell level, which combines the unique advantages of a high working voltage and a high discharge capacity. However, the design of the working electrode, which is the key to the battery performance, is absent in the literature. In this work, the electrode design of hybrid Zn-Co 3 O 4 /air batteries for performance improvements is investigated by considering the active material loading and the surface hydrophobicity of the Co 3 O 4 nanosheet-decorated carbon cloth electrode. The results demonstrate that the capacity of the Zn-Co 3 O 4 battery first dramatically increases with the loading, but the improvement becomes limited when the loading further increases. The discharge voltage plateau of the Zn-air battery increases first and then keeps decreasing. The reason is that although both the active material and the surface area increase, the increased dimension of nanosheets increases the transport resistance, especially for electrons and oxygen. For a given electrode, the discharge voltage of the Zn-air battery first increases with an increase of the hydrophobicity due to the creation of gaseous oxygen transport pathway, but then decreases due to the coverage of active sites. While both the voltage and the capacity of the Zn-Co 3 O 4 battery decrease with the hydrophobicity, which is attributed to the decreased contact surfaces between the reactant and the liquid electrolyte. Based on the optimized active material loading and surface hydrophobicity, a hybrid Co 3 O 4 /air battery delivers a high energy density of 936 Wh kg −1 (on the weights of Co 3 O 4 and consumed Zn) and stable discharge and charge voltages ranging from 0.94 V to 2.01 V for 400 cycles. This work illustrates that for high-performance hybrid batteries, the active material loading of the electrode should be well designed considering the transport of electrons and oxygen, and a balance between the hydrophobicity and hydrophilicity should be established. [ABSTRACT FROM AUTHOR]

Silicon-graphite composite electrode is one of the most practical solution for next generation high performance lithium ion batteries. Electrode geometry design is a new strategy to improve the electrochemical performances. Herein, we report a unique hierarchical structure of Si@alginate microcapsule-graphite composite anode, in which Si microcapsules are prepared by wrapping of calcium cross-linked alginate. The Si@alginate microcapsules are uniformly dispersed in graphite anode with the widely adopted CMC and SBR binder. The new geometry of electrode architecture has locally different binder systems, which enables both Si and graphite run in their optimized binder environment. The cross-linked alginate capsule effectively confines the volume change and prevents aggregation of the Si nano-particles, which contribute to a significant improvement of the electrochemical performances. At a weight ratio of 3:7 between Si and graphite, the composite electrode exhibits a reversible capacity of 916 mAh g −1 and a capacity retention of 92.4% after 200 cycles. The new strategy for hybrid anode represents a promising avenue for the mass production of high performance Si-graphite composite anode in the future. [ABSTRACT FROM AUTHOR]

Taking advantage of a high theoretical energy density of 2567 Wh kg -1 , lithium sulfur batteries (LSBs) have been considered promising candidates for next-generation energy storage systems. Nevertheless, challenging issues involving both sulfur cathode and lithium anode hinder their practical applications, which are followed by the extensive research efforts to resolve them. A wide variety of carbon nanomaterials with different characteristics has played an important role in enhancing the performance of LSBs via immobilizing sulfur in cathodes, accommodating the volume expansion of sulfur, enhancing the reaction kinetics and stabilizing lithium anodes. This report overviews the state-of-the-art progress in designing and fabricating nanocarbon for advanced LSBs with particular focuses on the correlations among porosity, electrical conductivity and surface chemistry as some of the most critical factors. More importantly, statistical analysis of electrochemical performance of batteries collected from literatures allows us to identify substantial disparities between the current achievements and the requirements for real-world applications. In an effort to bridge this gap, we highlight recent advances in the design of LSBs with improved sulfur loading, enhanced charge transfer and minimized electrolyte/sulfur ratio. Conclusions and perspectives for future development of nanocarbon in LSBs are proposed. [ABSTRACT FROM AUTHOR]

The electrocatalytic reduction of carbon dioxide (CO 2 RR) is a crucial technology to develop the decarbonisation strategy for carbon circularity and producing solar fuels substituting fossil fuels. This viewpoint discusses the role of the electrode and reactor design as the main factor in determining the performance of CO 2 RR, at least under reaction conditions relevant to industrial scalability, evidencing the need to overturn the current strategic vision focused more on improving the characteristics of the electrocatalytic materials. Many parameters characterising the performances (such as Faradaic efficiency, carbon selectivity and potential onset, besides the current density) are strongly influenced and typically dominated (under relevant conditions) by the effective population of adspecies on the electrode surface, which is, in turn, related to mass control and transport resistances, local pH changes, multiphase boundaries, wettability and other aspects. Even the preliminary screening of the catalysts could be incorrect, not operating under representative conditions, and thus without properly choosing the electrode and reactor. Advanced electrode/reactor designs, e.g., based on gas-diffusion electrodes (GDEs) that avoid having a liquid electrolyte (zero-gap design), are necessary to improve CO 2 RR scalability to industrial applications. Even in situ catalyst nanoparticle reconstruction may depend on these aspects. Electrochemical characterization methods like electrochemical impedance spectroscopy (EIS) are the right approach to study electrocatalytic reactions, providing crucial indications on the effective controlling elements that determine the electrocatalyst/electrode performances. [Display omitted] • status and perspectives for electrode and reactor design in CO2RR. • advanced electrode/reactor designs based on GDE and zero-gap design for the cell. • electrochemical impedance spectroscopy to understand the performance-controlling aspects. • role of mass control and transport resistances, local pH changes, multiphase boundaries. • role of electrode/reactor design in determining the mechanism of CO2 conversion. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) is one of the earliest non-traditional machining processes, based on thermoelectric energy between the workpiece and an electrode. In this process, the material is removed electro thermally by a series of successive discrete discharges between two electrically conductive objects, i.e., the electrode and the workpiece. The performance of the process, to a large extent, depends on the material, design and manufacturing method of the electrodes. Electrode design and method of its manufacturing also affect on the cost of electrode. Researchers have explored a number of ways to improve electrode design and devised various ways of manufacturing. The paper reports a review on the research relating to EDM electrode design and its manufacturing for improving and optimizing performance measures and reducing time and cost of manufacturing. The final part of the paper discusses these developments and outlines the trends for future research work.

Commercial lithium ion cells are now optimised for either high energy density or high power density. There is a trade off in cell design between the power and energy requirements. A tear down protocol has been developed, to investigate the internal components and cell engineering of nine cylindrical cells, with different power−energy ratios. The cells designed for high power applications used smaller particles of the active material in both the anodes and the cathodes. The cathodes for high power cells had higher porosities, but a similar trend was not observed for the anodes. In terms of cell design, the coat weights and areal capacities were lower for high power cells. The tag arrangements were the same in eight out of nine cells, with tags at each end of the anode, and one tag on the cathode. The thicknesses of the current collectors and separators were based on the best (thinnest) materials available when the cells were designed, rather than materials optimised for power or energy. To obtain high power, the resistance of each component is reduced as low as possible, and the lithium ion diffusion path lengths are minimised. This information illustrates the significant evolution of materials and components in lithium ion cells in recent years, and gives insight into designing higher power cells in the future.

An original 3D stochastic model, based on the truncated plurigaussian random fields, has been adapted to simulate the complex microstructure of SOC electrodes. The representativeness of the virtual microstructures has been checked on several synchrotron X-ray and FIB-SEM tomographic reconstructions obtained on typical LSCF, LSC and Ni-YSZ electrodes. The validation step has been carried out by comparing numbers of electrode morphological properties as well as the phase effective diffusivities. This analysis has shown that the synthetic media mimic accurately the complex microstructure of typical SOC electrodes. The model capability to simulate different types of promising electrode architectures has also been investigated. It has been shown that the model is able to generate virtual electrode prepared by infiltration resulting in a uniform and continuous thin layer covering a scaffold. With a local thresholding depending on the position, continuous graded electrodes can be also produced. Finally, the model offers the possibility to introduce different correlation lengths for each phase in order to control the local topology of the interfaces. All these cases illustrate the model flexibility to generate various SOC microstructures. This validated and flexible model can be used for further numerical microstructural optimizations to improve the SOC performances. [ABSTRACT FROM AUTHOR]

Objectives/hypothesis: The aims of this study were to investigate short- and long-term rates of hearing preservation after cochlear implantation and identify factors that impact hearing preservation.Study Design: Retrospective review.Methods: Patients undergoing cochlear implantation with conventional-length electrodes and air-conduction thresholds ≤80 dB HL at 250 Hz preoperatively were included. Hearing preservation was defined as air-conduction thresholds ≤80 dB HL at 250 Hz.Results: The sample included 196 patients (225 implants). Overall, the rate of short-term hearing preservation was 38% (84/225), with 18% (33/188) of patients preserving hearing long term. Multivariate analysis showed better preoperative hearing was predictive of hearing preservation at short (odds ratio [OR]: 0.93, 95% confidence interval [CI]: 0.91-0.95, P < .001) and long-term follow-up (OR: 0.94, 95% CI: 0.91-0.97, P < .001). Lateral wall electrodes and mid-scala electrodes had 3.4 (95% CI: 1.4-8.6, P = .009) and 5.6-times (95% CI: 1.8-17.3, P = .003) higher odds of hearing preservation than perimodiolar arrays at short-term follow-up, respectively. Long-term data revealed better hearing preservation for lateral wall (OR: 7.6, 95% CI: 1.6-36.1, P = .01), but not mid-scala (OR: 3.1, 95% CI: 0.4-23.1, P = .28), when compared to perimodiolar electrodes. Round window/extended round window (RW/ERW) approaches were associated with higher rates of long-term hearing preservation (21%) than cochleostomy approaches (0%) (P = 0.002) on univariate analysis.Conclusions: Better preoperative residual hearing, lateral wall electrodes, and RW/ERW approaches are predictive of higher rates of long-term functional hearing preservation.Level Of Evidence: 4. Laryngoscope, 128:482-489, 2018. [ABSTRACT FROM AUTHOR]

The application of integral shrouded blisks improves the aerodynamic efficiency and reliability of aerospace engines, while their semi-closed geometrical structures, high blade profile accuracy and difficult-to-cut material properties bring great challenges to their manufacturing. Electrical discharge machining (EDM) is regarded as an effective way to produce this kind of parts. In this paper, an electrode design method for EDM machining of integral shrouded blisks from a primitive electrode by electrode size reduction and electrode division was described. A new electrode feeding planning method named maximum free distance was presented, in which the position and attitude of a new electrode feeding path node was optimized by maximizing the distance that the electrode is able to move along a predefined reference direction before it interferes with the blisk. The feeding path sparsification was conducted to improve the workpiece debris evacuation and to save the machining time. The example of EDM machining an integral shrouded impeller with 1 in 2 out flow channels was given to validate the proposed electrode feeding path planning method. [ABSTRACT FROM AUTHOR]

High harvesting cost and reusing of post-harvest water are the major challenges in commercial production of microalgae. In this work, a flocculants-free electrolytic flotation harvest process was investigated. The electrode design and materials were evaluated in terms of harvesting efficiency. Stainless steel as the cathode and carbon as the anode were selected based on the harvesting efficiency data and non-sacrificial feature for construction of a pilot scale harvesting system. In the pilot scale experiments, 23.72 g/h biomass yield was achieved at the power consumption of 2.73 kWh/kg. With the advantages of no chemical flocculent contamination and relatively low energy requirement, this continuous system is promising for food or feed applications. [ABSTRACT FROM AUTHOR]

Silicon (Si) is one of the most promising next generation anode materials for lithium-ion batteries (LIBs), but the use of Si in LIBs has been rather limited. The main challenge is its large volume change (up to 300%) during battery cycling. This can lead to the fracture of Si, failure at the interfaces between electrode components, and large dimensional change on the cell level. To optimize the Si electrode/battery design, a model that considers the interactions of different cell components is needed. This paper presents the development of a multiphysics microstructure-resolved model (MRM) for LIB cells with a-Si anode. The model considered the electrochemical reactions, Li transports in electrolyte and electrodes, dimensional changes and stresses, property evolution with the structure, and the coupling relationships. Important model parameters, such as the diffusivity, reaction rate constant, and apparent transfer coefficient, were determined by correlating the simulation results to experiments. The model was validated with experimental results in the literature. The use of this model was demonstrated in a parameter study of Si nanowall|Li cells. The specific and volumetric capacities of the cell as a function of the size, length/size ratio, spacing of the nanostructure, and Li + concentration in electrolyte were investigated. [ABSTRACT FROM AUTHOR]

Objective: The vestibular implant seems feasible as a clinically useful device in the near future. However, hearing preservation during intralabyrinthine implantation remains a challenge. It should be preserved to be able to treat patients with bilateral vestibulopathy and (partially) intact hearing. This case study investigated the feasibility of hearing preservation during the acute phase after electrode insertion in the semicircular canals. Methods: A 40-year-old woman with normal hearing underwent a translabyrinthine approach for a vestibular schwannoma Koos Grade IV. Hearing was monitored using auditory brainstem response audiometry (ABR). ABR signals were recorded synchronously to video recordings of the surgery. Following the principles of soft surgery, a conventional dummy electrode was inserted in the lateral semicircular canal for several minutes and subsequently removed. The same procedure was then applied for the posterior canal. Finally, the labyrinthectomy was completed, and the schwannoma was removed. Results: Surgery was performed without complications. No leakage of endolymph and no significant reduction of ABR response were observed during insertion and after removal of the electrodes from the semicircular canals, indicting no damage to the peripheral auditory function. The ABR response significantly changed when the semicircular canals were completely opened during the labyrinthectomy. This was indicated by a change in the morphology and latency of peak V of the ABR signal. Conclusion: Electrode insertion in the semicircular canals is possible without acutely damaging the peripheral auditory function measured with ABR, as shown in this proof-of-principle clinical investigation. [ABSTRACT FROM AUTHOR]

Electrode design is investigated for electrical capacitance tomography on a 1 mm-thick 3D planar domain. Arrays of square electrodes are located on both sides of the domain, which is filled with dielectric material. Anomalies of interest are voids in the material with low dielectric constant. Simulated tomography is conducted with various electrode patterns over a range of electrode sizes in order to compare performance. The high-aspect-ratio domain requires a large finite element mesh for simulating electric fields and for defining spatial sensitivity responses of electrode pairs. Compared to the canonical 2D pipe cross-section problem, this high-aspect-ratio system requires solving the reconstruction problem on a much larger mesh and is more severely underdetermined. An efficient methodology for characterizing the sensitivity responses of various electrode pairs is developed. An image reconstruction algorithm creates binary images by sequentially composing a list of occupied cells, conditioned with a cell-to-cell energy formulation. A parametric study of four candidate electrode patterns is conducted using electrode sizes between 0.8 mm and 1.6 mm, in which each potential design is used to perform tomographic reconstruction of 100 images. A new image-error metric is proposed, which is used to evaluate each electrode design. It is found that an electrode matrix pattern on each substrate, with the patterns offset, results in lower mean image error than other candidate patterns. [ABSTRACT FROM AUTHOR]

Artificial neural network (ANN) is used to model active three/triple phase boundaries (TPBs) in solid oxide fuel cell (SOFC) electrodes composed of phases with various particle sizes for the first time in the literature. Electrode microstructures comprising catalyst, electrolyte and pore phases with the same volume fraction, but various mean particle sizes are synthetically generated via Dream.3D software and the active TPB densities are measured by COMSOL software to obtain input data for training the ANN models as well as to validate the network results. In this regard, three learning methods of Bayesian regulation (BR), Levenberg-Marquardt (LM) and Scaled conjugate gradient (SCG) with various hidden layer and neuron numbers are examined. Among ANN models with three inputs and one output, the model with BR including one hidden layer and five neurons performs the best. This model revealing an average relative error of only 0.036 is then employed to simulate SOFC electrodes microstructures with new particle sizes not introduced in the learning process. The active TPB densities estimated by ANN are found to agree well with the computed ones. Therefore, ANN modeling is considered as a useful tool for the prediction of active TPB density in SOFC electrodes after a careful selection of backpropagation method and network structure. [Display omitted] • ANN to model active TPB in terms of particle size for the first time in literature. • Synthetic SOFC electrode microstructures with various particle sizes are generated. • Active TPB densities are measured by COMSOL for training and validation. • Three learning methods with various hidden layers and neurons are studied. • Bayesian regulation with one hidden layer and five neurons performs the best. [ABSTRACT FROM AUTHOR]

Single-plate digital microfluidic devices offer a set of advantages over two-plate devices such as better mixing, the ability to move larger volumes, and easier access to the droplet. Currently, the non-floating configuration, where all non-energized electrodes on the device are grounded, is the most common electrode switching scheme used in single-plate devices. However, this scheme is limited by the symmetry of the electric field around the energized electrode, which can prevent complete droplet transport to the energized electrode for small droplets that can be seamlessly manipulated on two-plate devices. Here we present a numerical model to analyze the effect of droplet volume on the electrical forces generated on droplets actuated on single-plate digital microfluidic devices. We show that the commonly used non-floating switching scheme has a limit on the smallest droplet volume it can manipulate even if the droplet base diameter is larger than the electrode length; a condition that is currently believed sufficient for complete droplet movement. The model we built used Maxwell Stress tensor to calculate the electrical forces on the droplet to capture the effect of the grounding scheme more accurately than the contact angle change model. We used this model to analyze movability of droplets of various volumes and contact angles to find the minimum volume that can be successfully actuated. We also suggest better electrode designs that improve actuation of small droplets on single-plate devices and make their performance comparable to two-plate devices. [Display omitted] • Droplet full transport to the energized electrode is not guaranteed even if the diameter of the droplet base is larger than the electrode length. • Symmetry of the electric field may cause droplets to stop halfway to the energized electrode. • Analysis of the physics behind this behavior is presented through numerical modeling and preliminary experimentation. • New device designs that improve the movability of small droplets are presented. [ABSTRACT FROM AUTHOR]