Search Results (19)

The electrochemical cutting technique, utilizing electrolyte flushing through micro-hole arrays in the radial direction of a tube electrode, offers the potential for cost-effective and high-surface-integrity machining of large-thickness, straight-surface structures of difficult-to-cut materials. However, fabricating the array of jet micro-holes on the tube electrode sidewall remains a significant challenge, limiting the broader application of this technology. To enhance the efficiency and quality of machining these jet micro-holes on the tube sidewall, a helical electrode electrochemical drilling method assisted by anode vibration has been proposed. The influence of parameters, such as the rotational direction and speed of the helical electrode, as well as the vibration amplitude and frequency of the workpiece, on the machining results was investigated using fluid field simulation and machining experiments. It was found that these auxiliary movements could facilitate the renewal of electrolytes within the machining gap, thereby enhancing the efficiency and quality of electrochemical drilling. Using the optimized machining parameters, an array of 10 jet micro-holes with a diameter of 200 μm was machined on the metal tube sidewall. Electrochemical cutting with radial electrolyte flushing tests were then performed through these micro-holes. Full article

In recent years, 3D printing has emerged as a promising technology in energy storage, particularly for the fabrication of Li-ion battery electrodes. This innovative manufacturing method offers significant material composition and electrode structure flexibility, enabling more complex and efficient designs. While traditional Li-ion battery fabrication methods are well-established, 3D printing opens up new possibilities for enhancing battery performance by allowing for tailored geometries, efficient material usage, and integrating multifunctional components. This article examines three key 3D printing methods for fabricating Li-ion battery electrodes: (1) material extrusion (ME), which encompasses two subcategories—fused deposition modeling (FDM), also referred to as fused filament fabrication (FFF), and direct ink writing (DIW); (2) material jetting (MJ), including inkjet printing (IJP) and aerosol jet printing (AJP) methods; and (3) vat photopolymerization (VAT-P), which includes the stereolithographic apparatus (SLA) subcategory. These methods have been applied in fabricating substrates, thin-film electrodes, and electrolytes for half-cell and full-cell Li-ion batteries. This discussion focuses on their strengths, limitations, and potential advancements for energy storage applications. Full article

Low-melting-point Ga–xSn eutectic composites and natural silicate mineral powders were used as the electrode and solid-state electrolyte, respectively, in all-solid-state batteries for green energy storage systems. The influences of the Sn content in the Ga–xSn composite electrode on the electrochemical performance of the batteries were evaluated, and liquid composites with a Sn concentration of up to 30 wt.% demonstrated suitability for electrode fabrication through dip coating. Sodium-enriched silicate was synthesized to serve as the solid-state electrolyte membrane because of the abundance of water molecules in its interlayer structure, enabling ion exchange. The battery capacity increased with the Sn content of the Ga–xSn anode. The formation of intermetallic compounds and oxides (CuGa₂, Ga₂O₃, Cu₆Sn₅, and SnO₂) resulted in a high charge–discharge capacity and stability. The Ga–Sn composite electrode for all-solid-state batteries exhibits a satisfiable capacity and stability and shows potential for jet-printed electrode applications. Full article

Pastes containing reduced graphene oxide (rGO) and LiCl-Mn(NO₃)₂·4H₂O are screen-printed on a carbon cloth substrate and then calcined using a nitrogen atmospheric-pressure plasma jet (APPJ) for conversion into rGO-LiMnO_x nanocomposites. The APPJ processing time is within 300 s. RGO-LiMnO_x on carbon cloth is used to sandwich H₂SO₄, LiCl, or Li₂SO₄ gel electrolytes to form hybrid supercapacitors (HSCs). The areal capacitance, energy density, and cycling stability of the HSCs are evaluated using electrochemical measurement. The HSC utilizing the Li₂SO₄ gel electrolyte exhibits enhanced electrode–electrolyte interface reactions and increased effective surface area due to its high pseudocapacitance (PC) ratio and lithium ion migration rate. As a result, it demonstrates the highest areal capacitance and energy density. The coupling of charges generated by embedded lithium ions with the electric double-layer capacitance (EDLC) further contributed to the significant overall capacitance enhancement. Conversely, the HSC with the H₂SO₄ gel electrolyte exhibits better cycling stability. Our findings shed light on the interplay between gel electrolytes and electrode materials, offering insights into the design and optimization of high-performance HSCs. Full article

There has been some research on jet electrolytic processing at home and abroad, and the phenomenon of discharge during the process has been reported, but there has been little research on the mode of jet electrolysis with the aid of discharge. A jet mask electrolytic processing experiment was set up to prepare a blue oil mask on the surface of the workpiece using photolithography; two processing modes were achieved using different tool electrodes, the workpiece was processed by two types of motion, the processing micro-pits were observed morphologically using an optical microscope, and the test data were analyzed by plotting graphs. Experiments show that a blue oil mask with a thickness of 50 μm covers the workpiece to strengthen the fixity, and that jet electrolytic discharge machining can effectively improve the depth-to-width ratio by increasing the contribution to depth by 30%–38% and the contribution to width by 2%–18%, compared to jet electrolytic machining. The former has less island effect than the latter, with a flatter bottom and better-machined shape. Full article

Determining how to apply hydrogen as a therapeutic/preventive antioxidant for oxidative-stress-related diseases practically in daily life has not been studied. The effects of bathtubs and buckets filled with hydrogen water (41 °C, >10 min bathing) were investigated on six subjects, without a medical prescription, suffering from skin roughness on the foot, hand, finger, or elbow. They were also treated with an electrolyzer composed of a lattice-shaped, microscopically flat, platinum-plated three-layer electrode, except for one subject who was treated with a micro-porous emittance terminal hydrogen-jetting apparatus, resulting in improvements in both cases. For another subject with similar skin roughness on both hands, immersing the right hand in an electrolytically generated hydrogen water bucket showed more marked improvement than immersing the left hand in a bucket with normal water. The nano-bubbles (average, mode, and median sizes of 157 nm, 136 nm, and 94 nm, respectively) increased 3.79 fold to 2.20 × 10⁸/mL after 30 min electrolysis with 2 L of tap water and were boiling (98 °C, 2 min)-resistant, with heat stability in nano-bubbles as small as 69–101 nm, as evaluated by laser-beam-based Brownian movement trailing Nano-Sight analysis. The marked increase in nano-bubbles caused by electrolysis correlated with an increase in dissolved hydrogen (<15 μg/L to 527 μg/L) but not a decrease in dissolved oxygen (9.45 mg/L to 6.94 mg/L). Thus, the present study proposed the novelty of hydrogen regarding its contribution to health from the perspective that hydrogen-nano-bubble-rich water in a foot bucket, which was additively used together with a conventional bathtub and can be frequently used in daily life, improved diverse types of skin roughness. Full article

The electrostatic field-induced electrolyte jet (E-Jet) electric discharge machining (EDM) is a newly developed micro machining method. However, the strong coupling of the electrolyte jet liquid electrode and the electrostatic induced energy prohibited it from utilization in conventional EDM process. In this study, the method with two discharge devices connecting in serials is proposed to decouple pulse energy from the E-Jet EDM process. By automatic breakdown between the E-Jet tip and the auxiliary electrode in the first device, the pulsed discharge between the solid electrode and the solid workpiece in the second device can be generated. With this method, the induced charges on the E-Jet tip can indirectly regulate the discharge between the solid electrodes, giving a new pulse discharge energy generation method for traditional micro EDM. The pulsed variation of current and voltage generated during the discharge process in conventional EDM process verified the feasibility of this decoupling approach. The influence of the distance between the jet tip and the electrode, as well as the gap between the solid electrode and the work-piece, on the pulsed energy, demonstrates that the gap servo control method is applicable. Experiments with single points and grooves indicate the machining ability of this new energy generation method. Full article

Reduced graphene oxide (rGO) and/or polypyrrole (PPy) are mixed with chitosan (CS) binder materials for screen-printing supercapacitors (SCs) on arc atmospheric-pressure plasma jet (APPJ)-treated carbon cloth. The performance of gel-electrolyte rGO/CS, PPy/CS, and rGO/PPy/CS SCs processed by a dielectric barrier discharge plasma jet (DBDjet) was assessed and compared. DBDjet processing improved the hydrophilicity of these three nanocomposite electrode materials. Electrochemical measurements including electrical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charging-discharging (GCD) were used to evaluate the performance of the three types of SCs. The Trasatti method was used to evaluate the electric-double layer capacitance (EDLC) and pseudocapacitance (PC) of the capacitance. The energy and power density of the three types of SCs were illustrated and compared using Ragone plots. Our experiments verify that, with the same weight of active materials, the combined use of rGO and PPy in SCs can significantly increase the capacitance and improve the operation stability. Full article

Pastes containing reduced graphene oxide (rGO) and SnCl₂ solution were screen printed on carbon cloth and then calcined using a CO₂ tornado-type atmospheric-pressure plasma jet (APPJ). The tornado circulation of the plasma gas enhances the mixing of the reactive plasma species and thus ensures better reaction uniformity. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were performed to characterize the synthesized rGO-SnO₂ nanocomposites on carbon cloth. After CO₂ tornado-type APPJ treatment, the pastes were converted into rGO-SnO₂ nanocomposites for use as the active electrode materials of polyvinyl alcohol (PVA)-H₂SO₄ gel-electrolyte flexible supercapacitors (SCs). Various APPJ scanning times were tested to obtain SCs with optimized performance. With seven APPJ scans, the SC achieved the best areal capacitance of 37.17 mF/cm² in Galvanostatic charging/discharging (GCD) and a capacitance retention rate of 84.2% after 10,000-cycle cyclic voltammetry (CV) tests. The capacitance contribution ratio, calculated as pseudocapacitance/electrical double layer capacitance (PC/EDLC), is ~50/50 as analyzed by the Trasatti method. GCD data were also analyzed to obtain Ragone plots; these indicated an energy density comparable to those of SCs processed using a fixed-point nitrogen APPJ in our previous study. Full article

An electrochemical amperometric ethylene sensor with solid polymer electrolyte (SPE) and semi-planar three electrode topology involving a working, pseudoreference, and counter electrode is presented. The polymer electrolyte is based on the ionic liquid 1-butyl 3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTf₂] immobilized in a poly(vinylidene fluoride) matrix. An innovative aerosol-jet printing technique was used to deposit the gold working electrode (WE) on the solid polymer electrolyte layer to make a unique electrochemical active SPE/WE interface. The analyte, gaseous ethylene, was detected by oxidation at 800 mV vs. the platinum pseudoreference electrode. The sensor parameters such as sensitivity, response/recovery time, repeatability, hysteresis, and limits of detection and quantification were determined and their relation to the morphology and microstructure of the SPE/WE interface examined. The use of additive printing techniques for sensor preparation demonstrates the potential of polymer electrolytes with respect to the mass production of printed electrochemical gas sensors. Full article

Ball plasmoid discharges are a unique type of atmospheric-pressure plasma discharge with a lifetime on the order of a hundred milliseconds without attachment to a power source. These discharges are generated by a moderate current pulse over the surface of an aqueous electrolyte, and some consider the spherical plasmoid that results to bear some resemblance to ball lightning. This article presents the first analysis of the electrical properties of ball plasmoid discharges in a reversed-polarity configuration, i.e., with the central electrode serving as the anode rather than as the cathode. These experiments demonstrate that ball plasmoids can indeed be generated with either electrode polarity with similar observable properties. These results are contrary to what has previously been discussed in the literature and raise additional questions regarding formation mechanisms of ball plasmoids. Analysis of images and electrical measurements collected at various discharge energies show that two distinct processes occur during discharges with our circuitry and in this reversed-polarity configuration: the formation of spark channels between the anode and electrolyte, and the generation of streamers and a jet from the surface of the anode. Full article

This work focuses on the removal of perchloroethylene (PCE) from gaseous streams using absorbers connected with electrolyzers. Two types of absorption devices (jet absorber and absorption column) were compared. In addition, it has been evaluated the different by-products generated when a simultaneous electrolysis with diamond anodes is carried out. PCE was not mineralized, but it was transformed into phosgene that mainly derivates into carbon tetrachloride. Trichloroacetic acid was also formed, but in much lower amounts. Results showed a more efficient absorption of PCE in the packed column, which it is associated to the higher gas–liquid contact surface. Jet absorber seems to favor the production of carbon tetrachloride in gaseous phase, whereas the packed column promotes a higher concentration of trichloroacetic acid in liquid. It was also evaluated the scale up of the electrolytic stage of these electro-absorption devices by using a stack with five perforated electrode packages instead of a single cell. Clarification of the effect of the applied current density on the speciation attained after the electrolysis of the absorbent has been attempted. Experiments reveal similar results in terms of PCE removal and a reduced generation of gaseous intermediates at lower current densities. Full article

Electrochemical discharge machining (ECDM) refers to a non-traditional machining method for performing effective material removal on non-conductive hard and brittle materials. To increase the ECDM machining efficiency, traditionally, the method of increasing the machining voltage or increasing the electrolyte concentration is used. These methods can also cause overcut reaming of the drilled holes and a rough surface on the heat affected area. In this study, an innovative combinational machining assisted method was proposed and a self-developed coaxial-jet nozzle was used in order to combine two assisted machining methods, tool electrode rotation and coaxial-jet, simultaneously. Accordingly, the electrolyte of the machining area was maintained at the low liquid level and the electrolyte was renewed at the same time, thereby allowing the spark discharge to be concentrated at the contact surface between the front end of the tool electrode and the machined material. In addition, prior to the machining and micro-drilling, the output of the machining energy assisted mechanism was further controlled and reduced. For the study disclosed in this paper, experiments were conducted to use different voltage parameters to machine sapphire specimens of a 640 μm thickness in KOH electrolyte at a concentration of 5 M. Full article

The instability of machining process caused by the difficulty of the electrolyte refresh in electrochemical micromachining (EMM) of micro through-hole has been an unsolved problem. Thus, this paper investigates the electrochemical micromachining of micro through-hole by using a micro helical electrode combining with the jetting electrolyte. With the help of high-speed rotation of micro helical electrode and its spiral shape, the internal electrolyte can be stirred while the external jetting electrolyte can flow into the hole along the spiral groove to refresh the electrolyte effectively, thereby, improving the machining stability of EMM. Firstly, the influence of the process parameters on the fabrication of micro through-hole in the EMM by using micro helical electrode without non-conductive mask is investigated. Based on the optimization of the process parameters, a micro through-hole with an inlet dimension of 121.6 μm and an outlet dimension of 114.9 μm is obtained successfully. Furthermore, this paper also tries to use the micro helical electrode coated with the non-conductive mask to decrease the bad influence of the stray corrosion attack. It is found that the non-conductive mask coated on the surface of micro helical electrode can improve the machining accuracy significantly under the condition of low pulse frequency (≤1 KHz). However, its good effect on preventing the stray corrosion decreases along with the increase of the pulse frequency. Full article

Combining ink-jet printing and one of the most stable electroactive materials, PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)), is envisaged to pave the way for the mass production of soft electroactive materials. Despite its being a well-known electroactive material, widespread application of PEDOT:PSS also requires good understanding of its response. However, agreement on the interpretation of the material’s activities, notably regarding actuation, is not unanimous. Our goal in this work is to study the behavior of trilayers with PEDOT:PSS electrodes printed on either side of a semi-interpenetrated polymer network membrane in propylene carbonate solutions of three different electrolytes, and to compare their electroactive, actuation, and energy storage behavior. The balance of apparent faradaic and non-faradaic processes in each case is discussed. The results show that the primarily cation-dominated response of the trilayers in the three electrolytes is actually remarkably different, with some rather uncommon outcomes. The different balance of the apparent charging mechanisms makes it possible to clearly select one electrolyte for potential actuation and another for energy storage application scenarios. Full article