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[Display omitted] • Free-standing composite papers of SFCP@PANI were prepared. • The free-standing SFCP@PANI-2 paper was directly utilized as supercapacitive electrodes. • The SFCP@PANI-2 demonstrated an enhanced electrochemcial capacitive performance. Free-standing composite papers of SFCP@PANI were prepared by in situ polymerization of aniline on the surface of sisal fiber carbon paper (SFCP). The SFCP@PANI papers can be directly built into electrodes without the need for any binders or conductive agents. SFCP@PANI-2 exhibits excellent electrochemical performance in the three-electrode system and the coin-type symmetric supercapacitor (SSC), which indicates that it may be a promising electrode material for supercapacitor. [ABSTRACT FROM AUTHOR]

This study reports a unique flow-through electrode design for hydrogen production in alkaline water electrolysis. This paper investigates a variety of electrodeposition coatings on the 3D-printed electrodes, including nickel, nickel-copper, and nickel-iron. The catalytic activity and properties of the electrodes are examined through electrochemical measurements involving linear sweep voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy, and surface morphology analysis. An experimental setup is also developed to measure hydrogen production and evaluate the efficiency of the designed electrodes. The study finds the flow-through electrodes coated with nickel-copper and nickel-iron achieve the current densities of 54 mA/cm2 and 45 mA/cm2, respectively. The activation overpotentials for the nickel-copper coated electrode are reported as 539 mV, and 408 mV for the nickel-iron coated electrode, both at a current density of 10 mA/cm2. The highest production rate is obtained within the first 15 minutes, 0.273 μg/s for the Ni-Cu flow-through electrode and 0.255 μg/s for the Ni-Fe flow-through electrode. The study further shows that flow-through electrodes produce hydrogen with an efficiency approximately 74% higher than traditional electrodes, suggesting a potentially better design for better hydrogen production in industrial applications. • This study reports a new flow-through electrode design for hydrogen production. • The electrodes are fabricated using 3D-printing and coated using electrodeposition. • The performance is evaluated using electrochemical and hydrogen measurements. • The study finds that flow-through electrodes perform better than traditional. • The flow-through electrodes consume less energy with the same or higher production. [ABSTRACT FROM AUTHOR]

• The ORR reaction pathway and catalytic mechanism of rare earth-based catalysts are briefly described. • The latest progress of rare earth-based ORR catalysts is systematically summarized. • Rare earth elements play an indispensable role in improving the activity of electrocatalytic materials through the formation of heterostructure interface, doping/substitution engineering, strain effect, etc. Rare earth (RE) metals have special 4f shell electronic configuration and special physical and chemical properties. Therefore, rare-earth-based catalysts are extensive used in the electrochemical cathodic oxygen reduction reaction (ORR) of proton exchange membrane (PEM) fuel cells. However, the low conductivity and low active site density of these catalysts limit their effective application in electrochemistry. The results show that the oxygen reduction activity and stability of rare-earth-based catalysts can be significantly improved by controlling the electronic structure and spatial configuration of active sites through doping of metal/nonmetal elements. In this paper, the main research work on metal/nonmetallic element doping to improve the performance of rare earth-based-catalysts in recent years was reviewed, including noble metal element doping, non-noble metal element doping, non-metallic element doping, perovskite and so on. The paper further summarized and pointed out the problems and challenges faced by rare-earth-based catalysts, and looked forward to their development prospects and future research directions. In recent years, rare earth metals have been widely used in the electrochemical cathodic oxygen reduction (ORR) of fuel cells because of their special 4f shell electronic structure and special physical and chemical properties. However, the low conductivity and low active site density of these catalysts limit their effective application in electrochemistry. The results show that the electronic structure and spatial configuration of the active sites can be significantly improved by doping metal/non-metal elements, which can significantly improve the oxygen reduction activity and stability of the rare-earth based catalysts. In this paper, the main research work on improving the performance of rare earth-based catalysts doped with metal/non-metal elements at home and abroad in recent years is reviewed, and their development prospects and future prospects are also prospected. [Display omitted] [ABSTRACT FROM AUTHOR]

The hydrogen and oxygen bubbles covering the electrode surface will reduce the reaction rate of water electrolysis and increase energy consumption. Adding ultrasonic to the electrolytic cell can improve the escape velocity of bubbles on the electrode surface by oscillation and cavitation effect. In this paper, the effects of ultrasound on the performance of water electrolysis under different working conditions are studied by experiment and numerical simulation. Firstly, the polarization curves and bubble flow patterns under different positions of the ultrasonic vibrator and electrode were obtained through experiments. And then, the flow model of the electrolytic cell with ultrasonic is constructed, which considers the mass transfer between the gas and liquid phases and the acoustic flow phenomenon caused by cavitation. The results revealed that, due to the reflection of the wall and the transmission process of the ultrasonic in the electrolyte, the electrode position has a significant impact on the current density when the ultrasonic vibrator is located on the right side of the electrolytic cell, which can be increased by 2.40%–22.70% at different electrode positions compared with that without ultrasound. The influence of operating parameters on the flow field inside the electrolyzer was obtained through numerical simulation. As a result, appropriate loading methods and operating conditions can maximize the effectiveness of ultrasound. [Display omitted] • Improper ultrasonic loading method increases energy consumption. • Wall conditions have a significant impact on the performance of water electrolysis. • The bubble flow morphology on the electrode surface was observed. • A flow field model of electrolyzer with ultrasonic was constructed. [ABSTRACT FROM AUTHOR]

As a widely explored porous coordination polymer, metal-organic frameworks (MOFs) have great potential application in catalysis, sensing, gas storage and separation, their inherent poor conductivity limit their application in electrochemical domains. Therefore, the researchers introduced π-conjugated organic ligands to obtain conductive MOFs, presenting not only rich pores but also good conductivity. Review paper about synthesis and application of MOFs and MOF derivatives is hardly new. However, there are few reports on intrinsic conductive MOFs. In this paper, we review the charge transfer mechanism and preparation of intrinsic conductive MOFs, as well as their latest research advance in electrochemistry, including electrocatalysis, supercapacitor and sensing. In addition, the trends and challenges of conductive MOFs are also discussed. This paper provides a reference for the research of conductive MOFs in the field of electrochemistry. [Display omitted] • The charge transport mechanism of intrinsic conductive MOFs with π-conjugated structures is summarized. • From the composition of conductive MOFs, the synthetic methods of intrinsic conductive MOFs is explored. • The applications of intrinsic conductive MOFs in electrocatalysis, supercapacitor and electrochemical sensing are introduced. • New synthetic strategies of conductive MOFs complexes are proposed. • The future directions and challenges of conductive MOFs are given. [ABSTRACT FROM AUTHOR]

This paper introduces a design strategy for a self-assembled artificial solid electrolyte interface (SEI) layer with adjustable functional group integration, aimed at enhancing the performance of AZIBs. [Display omitted] • The self-assembled artificial SEI layer can securely adhere to the zinc surface through covalent bonding. • The resulting CF 3 -PSiOX layer acts as a hydrophobic shield, effectively isolating water and inhibiting corrosion. • The strong interaction between −CF 3 and Zn2+ guides the diffusion and deposition processes of Zn2+, optimizing the de-solvation process. Commercial applications of aqueous Zn batteries primarily encounter challenges related to surface corrosion and dendrite formation. In this study, a hydrophobic polysilane layer functionalized with −CF 3 groups (CF 3 -PSiO X) is tailored for Zn anode through a two-step process involving self-assembly and condensation. The CF 3 -PSiO X layer functions as a protective barrier, effectively isolating water and inhibiting corrosion. Moreover, the primary interactions between −CF 3 and Zn2+ guides the diffusion and deposition processes of Zn2+ while optimizing the de-solvation process, ultimately resulting in dendrite inhibition. Hence, cells with CF 3 -PSiO X layer boasts a high Coulombic efficiency (∼99.8 % after 1500 cycles), a long lifespan (over 2400 h), and optimized capacity retention (73.3 % over 1000 cycles). The self-assembled polysilane layer with customizable groups offers a novel approach for tuning the interface properties of Zn anodes and establishes a general principle for interface adjustment applicable to alternative metallic electrodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A PtX technology capable of removing methyl mercaptan from gas has been developed. • Electrochemically regenerated chlorine oxidizes methyl mercaptan and removes it. • The technology can purify gas to a high degree and is adaptable and scalable. • No Chlorine is released into the cleaned exhaust gas. • The final product of the oxidation is sulfate which is dissolved in the solvent. A new electroscrubbing technology has been developed. This Power-to-X process utilizes active chlorine, which oxidizes impurities and is continuously regenerated in an electrochemical cell. The process is primarily intended for hydrogen sulfide capture, but has shown potential in removing other sulfur components as well. In this paper the capability of the process for removing methyl mercaptan has been examined. The electroscrubbing process was able to remove mercaptan to undetectable levels. The capture rate of mercaptan was primarily determined by the applied electrical current. Gas flow and concentration had a negligible effect on the capture while liquid flow had only a minor impact. The primary product of the mercaptan oxidation was found to be sulfate ions. [ABSTRACT FROM AUTHOR]

The zinc powder replacement method for Co removal is characterized by several challenges, such as poor mass transfer and agglomeration. To solve this problem, the ultrasonically enhanced zinc powder replacement method was developed and used to remove Co from the sulfate solution, and a 95.02% removal rate of Co was achieved under the optimized condition. Compared with conventional conditions, the removal rate increased by 24.5%. The behavior and mechanism of zinc powder replacing Co were comprehensively analyzed through electrochemistry and COMSOL Multiphysics. Chronoamperometry curves showed that after the introduction of ultrasound, the reaction current increased by approximately two times compared with the conventional condition. The cyclic voltammetry (CV) curves showed that the reduction potential of Co positively shifted, accompanied by an increase in peak current. The electrochemical impedance spectroscopy (EIS) tests showed that the nuclear transmission resistance decreased by approximately 1.6 times compared with conventional conditions. In addition, the COMSOL simulation revealed that, after the system was subjected to ultrasonic conditions, the temperature, flow rate, and sound pressure physical field increased, which accelerated the heat and mass transfer process in the solution. The removal behavior of the system was studied using scanning electron microscopy and X-ray diffraction. Ultrasonic waves decomposed the insoluble substances on the surface of zinc powder, refined the particles, and improved the removal rate of Co. This provides new insights into the ultrasound-enhanced reaction. In this paper, we introduce an innovative approach by ultrasonic enhanced zinc powder for the replacement removal of cobalt, achieving high-efficiency cobalt elimination. Additionally, the electrochemical kinetics of the zinc powder replacement process is comprehensively investigated. Theoretical validation of ultrasound-enhanced heat and mass transfer processes within the solution was achieved through numerical simulations conducted using COMSOL software. [Display omitted] • Ultrasound was used to improve the efficiency of Co removal from zinc sulfate solution. • The removal rate was increased by 24.65% compared with convention. • The introduction of ultrasound increased the mass transfer in the solution. • Ultrasound decomposed the insoluble substance on the surface of the zinc powder. [ABSTRACT FROM AUTHOR]

• A interdigital flow field plate for PEM was designed based on plant vein system. • Two-phase flow behaviors and influences on electrolysis performance were studied. • Electrolysis performance was improved by eliminating the flow dead zone. Proton exchange membrane (PEM) electrolytic hydrogen production has the advantages of high current density, high operating pressure, wide power regulation range and so on. It has good adaptability to wind and photovoltaic power with high volatility and recognized as an important way to solve the effective utilization of renewable energy. In PEM electrolyzer cell (PEMEC), anode flow field plate plays a crucial role in the process of water electrolysis to produce oxygen, which affects the of gas and liquid transfer. Among them, the channel blockage caused by bubble retention is an important factor limiting the performance of PEMEC. In this paper, an interdigital flow field plate is designed based on the plant leaf vein system. The two-phase flow behaviors within the interdigital flow field channel are studied. The results show that the interdigital flow field plate is superior to the traditional serpentine flow field in terms of electrolytic efficiency and voltage loss. The reaction kinetics rate is accelerated, the overall ohmic resistance is reduced by about 4.8 %, and the hydrogen production is increased by about 9.1 %. The above research can provide guidance for the structural improvement and performance improvement of PEMEC. [Display omitted] [ABSTRACT FROM AUTHOR]

Additive manufacturing is a technique that allows the construction of prototypes and has evolved a lot in the last 20 years, innovating industrial fabrication processes in several areas. In chemistry, additive manufacturing has been used in several functionalities, such as microfluidic analytical devices, energy storage devices, and electrochemical sensors. Theophylline and paracetamol are important pharmaceutical drugs where overdosing can cause adverse effects, such as tachycardia, seizures, and even renal failure. Therefore, this paper aims at the development of miniaturized electrochemical sensors using 3D printing and polylactic acid-based conductive carbon black commercial filament for theophylline and paracetamol detection. Electrochemical characterizations of the proposed sensor were performed to prove the functionality of the device. Morphological characterizations were carried out, in which chemical treatment could change the surface structure, causing the improvement of the analytical signal. Thus, the detection of theophylline at a linear range of 5.00–150 μmol L−1 with a limit of detection of 1.2 μmol L−1 was attained, and the detection of paracetamol at a linear range of 1.00–200 μmol L−1 with a limit of detection of 0.370 μmol L−1 was obtained, demonstrating the proposed sensor effectively detected pharmaceutical drugs. [Display omitted] • A simple and easy printing miniaturized electrochemical device has been developed. • A 3D-printed sensor based on PLA and carbon black filament is constructed. • DMF chemical treatment was effective for exposing carbon black agglomerates. • The optimized method was applied for theophylline detection. • Drug monitoring is performed in pharmaceutical and artificial biological samples. [ABSTRACT FROM AUTHOR]

Rapid and sensitive determination of pesticide residues in fruits and vegetables is critical for human health and ecosystems. This paper used an Ag-modified CuO sphere-cavity array (CuO@Ag) electrode as a thiram SERS/electrochemical dual readout detection platform. Numerous Raman "hotspots" generated by uniformly distributed silver nanoparticles, charge transfer at the CuO@Ag interface, and the formation of Ag-thiram complexes contribute to the significant enhancement of this SERS substrate, which results in excellent SERS performance with an enhancement factor up to 1.42 × 106. When using SERS as the readout technique, the linear range of the substrate for thiram detection was 0.05–20 nM with a detection limit (LOD) of up to 0.0067 nM. Meanwhile, a correlation between the value of change in current density and thiram concentration was established due to the formation of stable complexes of thiram with Cu2+ generated at specific potentials. The linear range of electrochemical detection was 0.05–20.0 μM, and the detection limit was 0.0167 μM. The newly devised dual-readout sensor offers notable sensitivity and stability. The two signal readout methods complement each other in terms of linear range and detection limit, making it a convenient tool for assessing thiram residue levels in agro-food. At the same time, the combination of commercially available portable equipment makes on-site monitoring possible. Ag-modified CuO cavity arrays have been established as SERS-electrochemical dual-signal platforms for thiram detection. [Display omitted] • CuO@Ag cavity arrays were used as SERS/electrochemical dual-signal sensors. • The EM and CT synergistic effect endow CuO@Ag with excellent SERS performance. • The highly ordered array structure ensures excellent SERS signal reproducibility. • The complex between the electrode and thiram enhances the electrochemical response. • The sensor demonstrated the feasibility of detecting thiram in real samples. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) architected electrode materials are expected to exhibit advantageous properties such as enlarged surface area, increased mass transfer, enhanced adsorption and more active sites exposed. In this paper, boron-doped diamond (BDD) electrodes on 3D printed patterned silicon carbide (SiC) scaffolds have been fabricated using chemical vapor deposition (CVD). The stabilization of the plasma sphere by using clamshell type CVD reactor, introducing the outer protecting plate, the optimization of CVD parameters, and the design of 3D-SiC scaffolds improved the sp3/sp2 ratio, uniformity and growth rate of BDD. 3D-BDD electrodes exhibit enough electrical conductivity for electrochemical applications. The preliminary test for electrochemical carbon dioxide reduction (CO 2 R) has showed the potential advantages of this type of 3D structured BDD electrodes. [Display omitted] • Three-dimensional BDD electrode was fabricated on 3D-SiC scaffolds using microwave plasma chemical vapor deposition. • The stabilization of plasma improved the diamond growth on the 3D-structure. • 3D-BDD electrodes exhibited enough electrical conductivity for electrochemical applications. [ABSTRACT FROM AUTHOR]

Analysis of trace level metals in environmental samples (e.g., soil, water, and plant samples) is important for assessing environmental quality and food safety. This paper reports a non-toxic, eco-friendly, and cost-effective sensing method, capable of in-situ detection of microgram per liter (µg/L) levels of heavy metal ions in plant and soil solutions using carbon fiber electrodes (CFEs) produced without using any microfabrication. The electrochemical behaviors of the CFEs were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. As proof of principle, the CFEs were validated for sensing selected heavy metals in buffer solutions as well as in extracted plant and soil solutions using differential pulse anodic stripping voltammetry (DP-ASV). Experimental results confirm that the CFEs were able to simultaneously measure cadmium (Cd), lead (Pb), and mercury (Hg) with a detection limit of 2.10, 0.93, and 1.85 µg/L respectively in buffer solution, showcasing good selectivity and sensitivity. The ideal pH range for heavy metal detection was also extensively investigated and was found to be between pH 4.0 and pH 5.0. These findings lay a better foundation towards long-term and stable electrochemical analysis for plant and soil solution matrices. [Display omitted] • Carbon fiber electrode fabricated without using any microfabrication facility. • The sensor can detect Cadmium, Lead, and Mercury in a wide range between 10 and 1600 μg/L. • This sensor can detect heavy metals in a wide variety of solutions including buffer, plant, and soil solutions. • This sensor provides repeatability over 100 measurements. [ABSTRACT FROM AUTHOR]

[Display omitted] • The semiconducting properties of chalcopyrite is discussed. • Electrochemical characterization of chalcopyrite leaching passivation is reviewed. • The mechanisms of enhanced leaching of chalcopyrite are discussed. Chalcopyrite is the most important and abundant raw material for copper extraction in which hydrometallurgical leaching is more attractive. However, the leaching rate is limited, which is related to the properties of chalcopyrite and the passive film produced during leaching. Usually, the leaching of chalcopyrite is considered several electrochemical reactions whose redox processes, properties of passive film and substrate, mechanisms, and kinetics can be analysed by electrochemical characterizations (such as impedance plots (including Mott-Schottky curve and EIS plot), redox/open-circuit potential, potentiodynamic curves (including polarization curve and CV/LSV plot), and I - t / E - t curve) which are of easy manipulation, high efficiency, accuracy and credibility, and low cost and requirement. By initially introducing the properties of chalcopyrite and passive film, this paper reviews these recent electrochemical characterizations of chalcopyrite leaching and passivation, and the important electrochemical phenomenon-galvanic effect. The mechanisms of enhanced leaching, including manipulating lattice composition and structure, destroying p-n junction, regulating/attacking/hydrophilizing film, strengthening synergies, activating species/promoting diffusion, stabilizing cupric species by coordination, as well as improving adsorption, solid–liquid/intergranular electron transfer and galvanic effect, are also circumstantially discussed. To obtain more information about leaching and passivation, the joint use of several electrochemical characterizations is encouraged because of their different (dis)advantages. Finally, the prospect of chalcopyrite slurry electrolysis which integrates electrochemical leaching, ions purification and electrodeposition these three steps is envisaged. [ABSTRACT FROM AUTHOR]

Most products today have several functions, but these are achieved by integrating different monofunctional devices and/or materials in a system. Having several functions simultaneously in one single material has many potential advantages, such as a structural material that can also store energy, have self-sensing or self-healing capability or any other physical function. This would lead mass and resource savings, being more energy efficient and thus more sustainable. This paper presents a mini review on how carbon fibres can be used for integrating several functions simultaneously in a high-performance load carrying structural material using the electrical and electrochemical properties of carbon fibres. Through this carbon fibre composites can also store energy like a lithium-ion battery, be used as a strain sensor, have electrically controlled actuation and shape-morphing, and be used as an energy harvester. [ABSTRACT FROM AUTHOR]

• The scale inhibition mechanism of HAS was explored from three perspectives. • The main responsible for scale inhibition is carboxyl functional group of HAS. • There is a strong mutual attraction between HAS and the surface of calcite crystal. • The effect of HAS concentration on scale inhibition performance increases first and then decreases. The scale inhibition mechanism of sodium humate (HAS) on Calcium Carbinate (CaCO 3) was investigated by experiments, quantum chemical calculations and molecular dynamics simulations. The changes of electrochemical impedance spectroscopy were analyzed by electrochemical methods at different concentrations (0, 10, 30, 50, 70, 100 mg/L) of HAS. The molecular structure of HAS was optimized by quantum chemical calculation, and the charge distribution, electrostatic potential distribution and frontier orbital energy of HAS were obtained. The interaction simulation system between HAS and the crystal planes of calcite was constructed based on molecular dynamics simulation. The interaction mechanism between specific functional groups in HAS and calcite crystal plane was analyzed. The results show that the capacitance arc and charge transfer resistance increase with the increase of HAS concentration in the range of 0–50 mg. However, In the concentration range of 50–100 mg, the capacitance arc and charge transfer resistance decrease with the increase of concentration. In the optimized structure of HAS, the oxygen atom on the carboxyl group is more negatively charged. There is a strong mutual attraction between HAS and calcite crystal plane. The primary functional group responsible for achieving scale inhibition is formed through the bonding between the carboxyl oxygen atom within its molecular structure and the calcium atom on the calcite crystal plane. The research in this paper provides a strong guidance for the treatment of scale and the development of scale inhibitors. [ABSTRACT FROM AUTHOR]

A novel heterobinuclear heteroleptic μ-carbido-dimer complex (t Bu) 4 PcRu=C=FeTPP is capable of successful decomposing β-carotene without involvement any other reagent due to the activation of dioxygen molecule in some solvents. Interaction between the compound and t BuOOH in dichloromethane, benzene and acetonitrile afford highly reactive species which are catalytically competent in β-carotene, methylene blue and t BuOOH oxidation at room temperature. [Display omitted] Bimetallic µ-bridged complexes supported by macrocycles are worth addressing due to their excellent stability, rich redox chemistry and suitability in catalysis. This paper for the first-time reports on the synthesis and redox properties of an unexplored heterometallic μ-carbido-dimer derivative bearing iron-porphyrin and ruthenium-phthalocyanine parts and a FeIV = C = RuIV unit. The compound is identified by UV–visible, IR, EPR, MALDI TOF, electrochemistry techniques and DFT calculations. The redox activity of the compound toward H 2 O 2 , t BuOOH is examined. The results indicate that under oxidation conditions in dichloromethane, benzene and acetonitrile, the initial complex evolves rapidly via oxidation steps forming intermediates which are competent in β-carotene and methylene blue oxidation at room temperature. The site oxidation accessibility of the initial compound and the nature of high-charged intermediate species are established to depend on the solvent polarity and axial ligands. The findings contribute to a deeper understanding of the significant role of reaction conditions as well as the mixed macrocyclic ligand environment and metal nature in controlling the oxidizing capability and thus can aid the development of new more active and durable catalysts. [ABSTRACT FROM AUTHOR]

In this paper, porous NiTi intermetallic was synthesized via a modified thermal explosion (TE) method, utilizing Ni (74 μm, 38 μm, 5 μm, 100–200 nm) and Al element powders as raw material. The exothermic behavior and phase transition of porous NiTi intermetallic compounds were studied. The results showed that with the refinement of Ni particle size, the heat release decreased, and the Ti-74 μm sample was the product of two eutectic reactions. Their mechanical properties were verified by the Vickers hardness tester and universal testing machine, and the corrosion behavior of porous NiTi intermetallic compounds in phosphate-buffered saline (PBS) solution was studied by electrochemical tests. Among them, Ti-5 μm exhibits the most homogeneous microstructure and favorable mechanical properties, which has a porosity of 31.7 % and a compressive strength of 321.71 MPa. However, corrosion resistance is sacrificed due to the high open porosity. This study holds great promise for precise control microstructural characteristics and optimization of mechanical and electrochemical properties of porous NiTi intermetallics. • Porous NiTi intermetallic compounds were sintered by a rapid TE method. • The refinement of the particle size will limit the heat release of the TE reaction. • The prepared NiTi has a porosity of 31.7 % and a compressive strength of 321.71 MPa. • Reducing porosity contribute to improving corrosion resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • We introduce an innovative approach to electrochemical micromachining using a Two-tone sinusoidal signal and investigate the mechanism behind the reduced machining gap with this signal. • Using the Taguchi optimization method, we study the impact of the control variables on the micromachining process during micro-hole drilling, and results show that using the optimized parameters greatly enhanced processing accuracy. • We use this technology to machine the microstructures on 5-μm pure nickel sheet and hard-to-cut super alloy plates, and improve the machining accuracy to the nanometer level. Electrochemical micromachining is an emerging technology in the machining field. This method offers several advantages such as exceptional surface quality, minimal cathode depletion, and a high elimination rate. Often, an ultrashort pulse power supply is employed in electrochemical micromachining to address over-machining in non-processing areas. While reducing the pulse duration can enhance processing accuracy, its high cost and impracticality for regular production limit its development. This paper presents the use of a Two-tone sinusoidal signal as an alternative to ultrashort pulse in electrochemical micromachining. We investigated the mechanism behind the reduced machining gap with this signal. By drilling micro-holes in the nickel sheet to optimize parameters such as voltage, fundamental frequency, and harmonic order. Using the Taguchi optimization method, we studied the impact of these control variables on the micromachining process during micro-hole drilling. The study also focused on fabricating micro-structures using the best processing parameters. Our results showed that using the optimized parameters greatly enhanced processing accuracy. Moreover, we found that high machining accuracy could be achieved when working on hard-to-cut super alloy plates. [ABSTRACT FROM AUTHOR]