Electrodeposition Process Research Articles

Electrochemical study of an enhanced platform by electrochemical synthesis of three-dimensional polyaniline nanofibers/reduced graphene oxide thin films for diverse applications

This work reports the electrochemical fabrication of thin films comprising polyaniline nanofibers (PANI) in conjunction with graphene oxide (GO) and reduced graphene oxide (rGO) on ITO substrate, along with examining the electrochemical properties, with a focus on the influence of the substrate and electrolyte in the electrodeposition methods. The study explores the electrochemical characteristics of these thin films and establishes a flexible framework for their application in diverse sectors such as sensors, supercapacitors, and electronic devices. It analyzes the impact of the substrate and electrolyte in electrodeposition techniques. The effects were studied using techniques such as cyclic voltammetry and chronoamperometry. The fabrication process of PANI/GO and PANI/rGO thin films involved the integration of rGO within PANI via electropolymerization, conducted under sulfuric acid. GO was synthesized by modifying the well-known Hummers’ method and characterized by X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). SEM showed the diameters of the formed PANI were between 40 and 150 nm, which helped to intertwine the rGO nanosheets with PANI nanofibers to form thin films. The electrochemical behavior of the PANI/rGO thin films was examined using cyclic voltammetry (CV) and chronoamperometry in different electrolytes, including sulfuric acid (H₂SO₄) and potassium nitrate (KNO₃). The CV profiles exhibited distinct oxidation and reduction peaks, with variations in the voltammogram morphology attributed to the nature of the electrolyte and the substrate employed during the electrodeposition process. These results highlight the critical role of both the substrate and electrolyte in governing the electrochemical performance of PANI/rGO thin films. The findings from this study demonstrate a versatile approach for the fabrication of PANI/graphene-based thin films with tunable electrochemical properties, and such a strategy has great application to fabricating other thin film composites for supercapacitors or other control source frameworks requiring enhanced charge storage and electrochemical responsiveness.

The Form of Electrodeposited Iridium Ions in a Molten Chloride Salt and the Effects of Different Iridium Concentrations

A molten salt system was prepared using an optimized method. We studied the complex structure of Ir3+ ions in the molten salt system and the influence their concentration had on the quality of the coatings prepared via electrodeposition. Using TG-DSC and in situ XRD experiments, we studied the high-temperature characteristics and properties of IrCl3 alongside its thermal stability. Using in situ XRD and Raman spectroscopy, we analyzed the Ir ions’ complex structure and the variation in the molten salt system at high temperatures. Finally, the changes in the Ir ion concentration in the molten salt system and the influence of the microstructure of the coatings’ surfaces were investigated under different anode conditions. IrCl3 easily decomposes above 400 °C, and temperature increases accelerate the rate of this decomposition. When the NaCl-KCl-CsCl system is in a high-temperature, molten state, IrCl3 forms stable complex structures (IrCl6)3− and (IrCl6)2−, and the valence state of Ir will be transformed with the increase in temperature. Generating these complex structures is conducive to improving the Ir coating quality. During the electrodeposition process, too few Ir ions in the molten salt can lead to concentration polarization, affecting the quality of the coating. Application of the molten NaCl-KCl-CsCl system is conducive to the electrodeposition of Ir coatings in a suitable temperature range. At the same time, using Ir as the anode can enhance the quality of the coatings.

Recovery of Rhodium by Solvent Extraction using N, N, N′, N′, N″, N″-Hexahexyl-nitrilotriacetamide and Electrodeposition

The development of solvent extraction and direct electrodeposition processes is crucial for reducing the volume of secondary waste. In this study, the extraction behavior of Rh(III) using N, N, N, N′, N′, N′-hexahexyl nitrilotriacetamide (NTAamide(C6)) was investigated with three different diluents that have relatively high dielectric constants. Slope analysis revealed that the extraction mechanism of Rh(III) is based on ion-pair extraction. The electrochemical behavior of the extracted Rh(III) complexes in each diluent was investigated using cyclic voltammetry. Rh(III) was reduced to Rh(0) through a three-electron transfer in the NTAamide(C6)/acetophenone, 1,2-dichloroethane, and 1-octanol systems. Moreover, the diffusion coefficient of the extracted Rh(III) complex was evaluated using semi-differential analysis. The electrodeposits were recovered through continuous solvent extraction and direct electrodeposition. The electrodeposits were identified as Rh metals by X-ray photoelectron spectroscopy and X-ray diffraction analyses.

Innovative Zinc Anodes: Advancing Metallurgy Methods to Battery Applications.

Aqueous zinc metal batteries (AZMBs) are emerging as a powerful contender in the realm of large-scale intermittent energy storage systems, presenting a compelling alternative to existing ion battery technologies. They harness the benefits of metal zinc's high safety, natural abundance, and favorable electrochemical potential (-0.762V vs Standard hydrogen electrode, SHE), alongside an impressive theoretical capacity (820mAhg-1 and 5655mAhcm-3). However, the electrochemical performance of ZMBs is impeded by several challenges, including poor compatibility with high-loading cathodes and persistent side reactions. These issues are intricately linked to the inherent physicochemical properties of the zinc metal anodes (ZMAs). Here, this review delves into the traditional methods of ZMAs production, encompassing extraction, electrodeposition, and rolling processes. The discussion then progresses to an exploration of cutting-edge methodologies designed to enhance the electrochemical performance of ZMAs. These methods are categorized into alloying, pre-treatment of substrate, advanced electrodeposition techniques, and the development of composite anodes utilizing zinc powder. The review offers a comparative analysis of the merits and drawbacks of various optimization strategies, highlighting the beneficial outcomes achieved. It aspires to inspire novel concepts for the advancement and innovation of next-generation zinc-based energy storage solutions.

Electrochemical Nucleation and Growth Mechanism of Metals

AbstractThis review provides a detailed analysis of the current transition observed in the field of electrodeposition of metals. Special emphasis is placed on the mechanism initiated by nucleation followed by diffusion‐controlled growth. The study highlights recent advances, relevant theoretical models, and practical implications of this process. Concrete examples are also discussed to illustrate the application of this method in various industrial and scientific contexts. These promising advances open new perspectives for the optimization of electrodeposition processes, paving the way for innovative applications in various technological sectors.

Electrodeposition of Cu 3D structures suitable for CO2 reduction

Porous Cu foam electrodes, suitable for cathodic CO2 reduction, were deposited in an acidic sulphate solution with different additives to obtain structures with a high real surface area and an adequate mechanical stability. The influence of the electrodeposition time and solution composition on the porosity parameters, microstructure and stiffness of Cu 3D structures was evaluated. Neither ammonium acetate nor polyethylene glycol were found to be effective additives to the Cu sulphate electrolyte to achieve the main objectives. Only the presence of Cl– ions in the deposition solution resulted in a threefold increase in the real surface area and the achievement of a sufficient mechanical stability of the Cu 3D structure. The latter effect is related to the specific influence of Cl– ions during the electrodeposition process on the microstructural characteristics, such as the size of micropores in the walls of holes and crystallite aggregates that form dendritic branches. These structural changes, in contrast to the Cu samples deposited in a solution without additives, resulted in larger real surface areas, while the denser structures deposited in the presence of Cl– ions ensured the mechanical stability of the 3D structure.

Electrodeposition and optimisation of amorphous NixSy catalyst for hydrogen evolution reaction in alkaline environment.

Anion exchange membrane (AEM) water electrolyser has shown its potential in green hydrogen production. One of the crucial tasks is discover novel cost-effective and sustainable electrocatalyst materials. In this study, a low-cost Ni-S-based catalyst for hydrogen evolution reaction was prepared via a simple electrodeposition process from a modified Watts bath recipe. Physical characterisation methods suggest this deposit film to be amorphous. Optimisation of the electrodeposition parameters of the NixSy catalyst was carried out using a rotating disk electrode setup. The optimised catalyst exhibited excellent catalytical performance in 1 M KOH on a microelectrode, with overpotentials of 41 mV, 111 mV and 202 mV at 10, 100 and 1000 mA cm-2 with Tafel slope of 67.9 mV dec-1 recorded at 333 K. Long-term testing of the catalyst demonstrated steady performance over a 24 h period on microelectrode at 100 mA cm-2 with only 71 mV and 37 mV overpotential increase at 293 K and 333 K respectively. Full cell testing with the optimised NixSy as cathode and NiFe(OH-)2 as anode showed 1.88 V after 1 h electrolysis at 500 mA cm-2 in 1 M KOH under 333 K with FAA-3-30 membrane.

Composite electrochemical coatings of Ni-CrB2 from sulfuric acid and sulfamate electrolytes: formation, structure and properties

Electrodeposited coatings are in demand in many industries: due to the high adhesive strength to the base metal, they can be applied to complex-shaped products, and the thickness of the deposited coating can be controlled. However, standard electrolytic coatings do not always meet the necessary operating requirements. In this case, the formation of composite electrolytic coatings, which consist in the modification of electrolytes by various dispersed particles, becomes an urgent task. These particles are introduced into the electrolyte and deposited together with the precipitate metals, which leads to changes in the coating properties. In this article, the structure, adhesive and corrosion properties of nickel-chromium diboride composite coatings obtained in the electrodeposition process are studied. Precipitation was carried out in sulfuric acid and sulfamate electrolytes with a concentration of dispersed chromium diboride particles of 10-40 g/l. The coatings consist of nickel and CrB2 phases. The adhesive strength of the coating with a steel base is satisfactory; chipping and peeling were not observed. The corrosion resistance of sulfamate electrolyte coatings is higher than that of the coatings obtained from sulfuric acid electrolyte due to the compactness of nickel precipitates. Chromium diboride in the coating provides 1.5-2 times greater corrosion resistance.

Dynamically Favorable Ion Channels Enabled by a Hybrid Ionic-Electronic Conducting Film toward Highly Reversible Zinc Metal Anodes.

Aqueous zinc ion batteries show great promise for future applications due to their high safety and ecofriendliness. However, nonuniform dendrite growth and parasitic reactions on the Zn anode have severely impeded their use. Herein, a hybrid ionic-electronic conducting ink composed of graphene-like carbon nitride (g-C3N4) and conductive polymers (CP) of poly(3,4ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) is introduced to Zn anode using a scalable spray-coating strategy. Notably, the g-C3N4 promotes a screening effect, disrupting the coulombic interaction between the PEDOT+ segments and PSS- chains within CP, thereby reducing interfacial resistance and homogenizing the surface electric field distribution of the Zn anode. Furthermore, the abundant N-containing species and ─SO3 - groups in g-C3N4/CP exhibit strong zincophilicity, which accelerates the diffusion of Zn2+ and disrupts the solvation structure of Zn(H2O)6 2+, thus improving the Zn2+ transfer capability. Consequently, the g-C3N4/CP can powerfully stabilize the Zn2+ flux and thus enable a high coulombic efficiency of 99.47% for 1500 cycles and smooth Zn plating/stripping behaviors more than 3000h at a typical current density of 1mA cm-2. These findings shed new light on the Zn electrodeposition process under the mediation of g-C3N4/CP and offer sustainability considerations in designing more stable Zn-metal anodes with enhanced reversibility.

Thin Zinc Electrodes Stabilized with Organobromine-Partnered H2O-Zn-MeOH Cluster Ions for Practical Zinc-Metal Pouch Cells.

The utilization of thin zinc (Zn) anodes with a high depth of discharge is an effective strategy to increase the energy density of aqueous Zn metal batteries (ZMBs), but challenged by the poor reversibility of Zn electrode due to the serious Zn-consuming side reactions at the Zn||electrolyte interface. Here, we introduce 2-bromomethyl-1,3-dioxolane (BDOL) and methanol (MeOH) as electrolyte additive into aqueous ZnSO4 electrolyte. In the as-formulated electrolyte, BDOL with a strong electron-withdrawing group (-CH2Br) tends to pair with the H2O-Zn-MeOH complex, leading to the formation of organobromine-partnered H2O-Zn-MeOH cluster ions. During the Zn electrodeposition process, the formed ZnO-dominated by-products induce the polymerization of BDOL monomers, which are previously adsorbed on the electrode. As a result, a uniform dual-layer SEI with ZnO-dominated outer layer and polyether-dominated inner layer is built on the surface of Zn electrode. With such an in-situ formed dual-layer SEI, the Zn||Mg0.9Mn3O7·2.7H2O pouch cell using a 10-um Zn anode (corresponding to a low negative to positive areal capacity ratio of 3.56) successfully operated for 300 cycles with a high capacity retention of 86%, promising a high practical energy density of > 120 Wh/kg (based on the total mass of Zn and Mg0.9Mn3O7·2.7H2O).

Glucose Oxidation Performance of Zinc Nano-Hexagons Decorated on TiO2 Nanotube Arrays

Electrochemically anodized TiO2 nanotube arrays (NTAs) were used as a support material for the electrodeposition of zinc nanoparticles. The morphology, composition, and crystallinity of the materials were examined using scanning electron microscopy (SEM). Electrochemical impedance spectroscopy (EIS) was performed to evaluate the electrochemical properties of TiO2 NTAs. Annealing post-anodization was shown to be effective in lowering the impedance of the TiO2 NTAs (measured at 1 kHz frequency). Zinc nanohexagons (NHexs) with a mean diameter of ~300 nm and thickness of 10–20 nm were decorated on the surface of TiO2 NTAs (with a pore diameter of ~80 nm and tube length of ~5 µm) via an electrodeposition process using a zinc-containing deep eutectic solvent. EIS and CV tests were performed to evaluate the functionality of zinc-decorated TiO2 NTAs (Zn/TiO2 NTAs) for glucose oxidation applications. The Zn/TiO2 NTA electrocatalysts obtained at 40 °C demonstrated enhanced glucose sensitivity (160.8 μA mM−1 cm−2 and 4.38 μA mM−1 cm−2) over zinc-based electrocatalysts reported previously. The Zn/TiO2 NTA electrocatalysts developed in this work could be considered as a promising biocompatible electrocatalyst material for in vivo glucose oxidation applications.

Effect of ANSA as an additive on electrodeposited Sn-Ag-Cu alloy coatings in deep eutectic solvent

This study investigates the electrodeposition of Sn-Ag-Cu ternary solder coating in a choline chloride-ethylene glycol DES using 1-amino-2-naphthol-4-sulfonic acid (ANSA) as an additive. The mechanism of ANSA was evaluated through UV–visible absorption spectroscopy, infrared spectroscopy, and CV. The results demonstrate that ANSA, as a multifunctional organic compound, influences the electrodeposition process through its sulfonic acid, amino, and naphthyl groups. When the ANSA concentration is below 600 ppm, its primary action is through an interfacial adsorption mechanism, where lone pairs of electrons on nitrogen and oxygen atoms adsorb onto the electrode surface, and the bulky naphthyl ring inhibits the formation of large deposits. As the ANSA concentration exceeds 600 ppm, complexation becomes the dominant mechanism, competing with the complexation of chloride ions (Cl−) in the choline chloride electrolyte. SEM analysis indicates that as the ANSA concentration increases, the deposited coatings become smoother, denser, and exhibit finer grain sizes. The Scharifker-Hills model was employed to analyze the CA curves before and after the addition of ANSA, revealing that the nucleation mechanism of Sn-Ag-Cu alloy deposition gradually transitions from instantaneous nucleation to progressive nucleation with increasing ANSA concentration.

Facile synthesis of high-performance free-standing hierarchically porous NiO/Bi@Bi2O3 hybrid electrode for supercapacitors

By tactfully utilizing the different chemical characteristics of Bi and Ni element in the electrodeposition process, this work successfully designs a novel free-standing NiO/Bi@Bi2O3 hybrid electrode with dual electroactive components (NiO and Bi@Bi2O3) and hierarchically porous structure. After co-electrodeposition, the porous Bi metal as a conductive skeleton can effectively improve the electrical conductivity of the electrode. Moreover, Bi2O3 and NiO have synergistic effects by modifying the electronic structure. The newly developed bimetallic NiO/Bi@Bi2O3 hybrid electrode exhibits high volumetric capacitance value of 1166.67 F cm−3, which is attributed to the dual advantages of structure and composition. This work provides a new idea for the design of high-performance transition metal oxide-based electrodes.

Electrolyte Solution Stirring Effect on Deposition Rate, Crystallographic Orientation, and Electrochemical Behaviour of Ni Film

Abstract Stirring the electrolyte meanwhile electrodeposition process is running may influence the properties of the forming films. In this work, the electrodeposition of copper (Cu) over aluminium (Al) alloy was performed. Subsequently, the electrodeposition of nickel (Ni) onto the formed Cu layer was conducted. In order to enhance the films properties, some various stirring speeds then are implied on the plating solution of the Ni electrodeposition process. The synthesized of Ni films were analysed by means of both X-ray diffraction (XRD) and a potentiostat equipment. The sample made shows different physical properties before and after electrodeposition based on sample weighed to examine the deposition rate. XRD patterns confirmed that all samples have a face-centered cubic (fcc) crystal structures with a space group of Fm-3m. Stirring speed play an important role of an inverse relationship with deposition rate, crystallite size, lattice strain, and corrosion rate. The sample that was made using the highest stirring speed yield a better corrosion resistance at around 0.239 mmpy due to less lattice strain.

Ionic buffer layer design for stabilizing Zn electrodes in aqueous Zn-based batteries

Aqueous Zn-based batteries (AZBs) are hindered by issues associated with the Zn electrodeposition process (ZEDP) on electrode surfaces, including passivation, dendrite formation, and hydrogen evolution. One of the important reasons is the drastic fluctuation in the concentration of Zn2+ ions on the electrode surface during the charging and discharging process. In this work, an electrolyte with Zn2+ ion buffer layer (EZIBL) is proposed to regulate the ZEDP. First, numerical simulations and corresponding experiments are conducted to assess the impact of different thicknesses of the Zn2+ ion buffer layer (ZIBL) on the variation in Zn2+ ion concentration, from which the optimal thickness of the ZIBL is determined. Then, the regulation role of EZIBL in the cycling process is demonstrated by a Zn-Cu half cell. Further, combined with the potential profile of the symmetric cell and the experimental phenomena, the regulation role of EZIBL in ZEDP is systematically explained at the mechanistic level through the analysis of key parameters. Finally, a full battery composed of Zn-LiMn2O4 is assembled to evaluate the practical applicability of the EZIBL in real battery cycles, which shows great enhancement in capacity retention and Coulombic efficiency. This work proposes the design of the EZIBL used to regulate the ZEDP and provides a simple, low-cost regulation method for the development of high-performance AZBs.

Pretreatments for photoresist-patterned wafer to improve Cu pillar electrodeposition

Cu micropillars are essential components in the electronics packaging, basically connecting multiple chips. The pillars are fabricated by Cu electrodeposition that fills inside via holes formed through a photoresist (PR) layer. Unlike Damascene and TSV processes, the Cu seed layer is only opened at the bottom of via holes, while the rest of the wafer surface is covered by the PR. Therefore, additional pretreatments are required to improve the Cu electrodeposition process due to air bubbles entrapped inside PR holes, organic residues, and native oxide on Cu seed layers. This research systematically investigated the pretreatments for PR-patterned wafers. A humidifier, hot steam, and compressed water spray were assessed for surface hydration to remove air bubbles from the PR holes. Ethanol- and citric acid-based aqueous solutions were then applied to remove organic residues and native oxide from the surface of Cu seed layers. The advantages of these pretreatments were assessed by analyzing the quality of Cu electrodeposits, and the optimum methods and solutions for Cu pillar electrodeposition on the PR-patterned wafer were suggested.

Preparation of Cu nanolayers by magnetic field-assisted electrodeposition and research on the nucleation and growth mechanism

Electrodeposition technology is widely used in the surface treatment of copper foil, and the core of this technology is roughening and curing treatment. During the electrodeposition process, the deposited layers often exhibits some problems, such as coarse grain size, uneven thickness and difficult control of crystal morphology. The magnetohydrodynamic (MHD) effect of magnetic field can obviously control the electrodeposition of Cu and improve the micro-morphology and performance of deposited layers. In this paper, Linear Sweep Voltammetry (LSV), Cyclic Voltammetry (CV) and Chronocoulometry (CC) curves were adopted to investigate the electrochemical behavior of deposited Cu in ultra-high acidity sulfate systems under different magnetic field conditions. The nucleation and growth mechanism were discussed, and the micro-morphology of deposited layers was analyzed. The results show that the electrodeposition of Cu follows the three-dimensional (3D) growth mechanism of progressive nucleation and diffusion control under the static condition, and the deposits appear cylindrical shape formed by spherical agglomerated. The magnetic field significantly improves the mass transfer rate, and the deposited layers will be more uniform and dense, following 3D growth mechanism under the electrochemical control. With the increasing of magnetic field intensity, the nucleation mechanism gradually shifts from progressive to transient nucleation. At the early stage of nucleation, the high-intensity magnetic field can significantly increase the number of grains and refine them, obtaining uniform and dense deposited nanolayers.

A Comparative Study on the Corrosion Resistance and Long-Term Stability of Hierarchical Superhydrophobic Nickel Coatings Obtained by One-Step and Two-Step Electrodeposition Processes

A Comparative Study on the Corrosion Resistance and Long-Term Stability of Hierarchical Superhydrophobic Nickel Coatings Obtained by One-Step and Two-Step Electrodeposition Processes

Nickel-copper alloying arrays realizing efficient co-electrosynthesis of adipic acid and hydrogen

Constructing electrocatalytic overall reaction technology to couple the electrosynthesis of adipic acid with energy-saving hydrogen production is of significant for sustainable energy systems. However, the development of highly-active bifunctional electrocatalysts remains a challenge. Herein, 3D hierarchical nickel-copper alloying arrays with dendritic morphology are manufactured by a simple electrodeposition process, standing for the excellent bifunctional electrocatalyst towards the co-production of adipic acid and H2 from cyclohexanone and water. The membrane-free flow electrolyzer of Cu0.81Ni0.19/NF shows the superior electrooxidation performance of ketone-alcohol (KA) oil with high faradaic efficiencies of over 90% for adipic acid and H2, robust stability over 200 h as well as a high yield of 0.6 mmol h−1 for adipic acid at 100 mA cm−2. In-situ spectroscopy indicates the Cu0.81Ni0.19 alloy contributes to forming more active NiOOH species to involve in the conversion of cyclohexanone to adipic acid, while the proposed reaction pathway undergoes the 2-hydroxycyclohexanone and 2,7-oxepanedione intermediates. Moreover, the theoretical calculations confirm that the optimal electronic interaction, boosted reaction kinetics as well as improved adsorption free energy of reaction intermediates, synergistically endows Cu0.81Ni0.19 alloy with superior bifunctional performance.

Study of Chemical Reactions in Molten Salts By Electrochemical Transient Techniques

Processes of electrodeposition and electrochemical synthesis in many cases are accompanied by chemical reactions. In the present work, the following chemical reactions: comproportionation, disproportionation, displacement, cluster formation, heteronuclear complex formation, polymerization, competitive complex formation, and acidic-basic have been studied by electrochemical transient techniques. The effect of chemical reactions on the composition of electrolysis products is discussed and methods of suppressing the reactions complicating the electrolysis processes are suggested. The results of the synthesis of functional materials using chemical reactions are presented.