Electrochemical Co-deposition Research Articles

Preparation of coaxial Sn-Co alloy/CNFs 3D freestanding membrane anode by electrochemical Co-deposition for lithium-ion batteries

Coaxial Sn-Co alloy/CNFs nanocomposite three-dimensional (3D) membrane is synthesized via a facile electrochemical co-deposition method using the CNFs membrane with 3D network structure as the flexible freestanding substrate. The as-synthesized nanocomposite membrane is characterized using scanning electron microscopy (SEM), transition electron microscopy (TEM), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD). The results reveal that nanoscaled Sn-Co alloy layer is uniformly covered onto the surface of CNFs; the thickness of Sn-Co alloy shell layer can be controlled to about 60–110 nm. EDS result exhibits that the atomic percentage of Sn, Co, and C in the as-synthesized nanocomposite membrane is 53.25 at%, 20.19 at%, and 26.56 at%, respectively. The nanocomposite membrane with the unique 3D network structure is flexible after Sn-Co alloy deposition. Its electrochemical performances are investigated by the cyclic voltammetry, galvanostatic charge/discharge cycling, and rate cycles. Its discharge specific capacity for 2nd and 50th cycle is 1260 mAh g−1 and 788 mAh g−1, respectively, and the capacity attenuation ratio is about 0.75%/cycle at a current density of 50 mA g−1. The excellent electrochemical performance of the coaxial Sn-Co alloy/CNFs nanocomposite 3D membrane is mainly contributed to the high mechanical strength, good flexibility, and high electrical conductivity of CNFs substrate, which offers a possible solution of Sn volume change and poor electronic conduction during charge/discharge process.

Lithiophobic-lithiophilic composite architecture through co-deposition technology toward high-performance lithium metal batteries

Metallic lithium (Li) has been acclaimed as the most promising anode materials for lithium batteries due to its ultrahigh theoretical capacity of 3860 mA h g−1. Its practical application is impeded, however, due to the notorious problems related to dendrite growth caused by its uneven current density distribution and high Li nucleation overpotential. Here, we report a three-dimensional (3D) lithiophobic phase (Cu) and lithiophilic phase (Zn or Sn) composite architecture realized through a facile electrochemical co-deposition technology and its use as a scaffold for dendrite-free Li metal anode. It is found that the simultaneous formation of this lithiophobic-lithiophilic composite on Cu foam leads to ultrafine lithiophilic phase (20 nm) and reduced Li nucleation overpotential, as well as enhanced homogeneity, which enables a uniform electric field distribution during lithium plating/stripping, thus facilitating even and dendrite-free Li deposition. In the meanwhile, the lithiophobic component in the composite acts as a strong backbone, helping to maintain structural stability during lithium storage. Also, the as-prepared three-dimensional micro/nanoporous scaffold with large surface area can effectively reduce the local current density and suppress Li dendrite growth. The full cells with the composite architecture/Li as anode and LiFePO4 as cathode show promising electrochemical performance with over 80% capacity retention over 1600 cycles at 5 C. This work broadens the horizon of lithiophilic hosts for next-generation high-performance Li metal batteries.

Evaluation of the electrocatalytic activity and stability of graphene oxide nanosheets coated by Co/Ni elements toward hydrogen evolution reaction

Electrocatalytic properties of a novel Graphene Oxide (GO) electrode combined with the cobalt/nickel (Co+Ni/GO) nanoparticles were investigated using Hydrogen Evolution Reaction (HER). The (Co+Ni)/GO electrode was synthesized in two steps. First, the GO nanosheets coating was pulse reverse electrodeposited from 0.5 mg ml−1 of GO suspension. Then, a coating modified by the electrochemical deposition of Co and Ni ions was obtained by the chloride salts. Microstructure, phase content, topography, and functional groups of the thin films were studied by the field emission scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, atomic force microscopy, Fourier transform infrared spectrometer experiments, transition electron microscopy, and x-ray photoelectron microscopy. Moreover, the electrocatalytic activity of fabricated electrodes was studied using LSV and EIS while and electrocatalytic stability was evaluated via chronoamperometry test. The results demonstrated that the Tafel slope and overpotential of the electrode in the HER current density of 10 mA cm−2 are mainly decreased to 64 mV dec−1 and 200 mV versus RHE, respectively, for the (Co+Ni)/GO electrode. The suitable electro-activity and acceptable stability of the modified (Co+Ni)/GO shows that this electrode can be a good candidate in HER application.

Low-temperature electrochemical codeposition of aluminum-neodymium alloy in a highly stable solvate ionic liquid

A highly stable solvate ionic liquid comprising a 2:1 (mol/mol) mixture of ethylene carbonate (EC) and AlCl3 was used for near room-temperature electrochemical codeposition of an Al-Nd alloy using chlorides as precursors. This liquid is low-cost, easy to prepare, and has high electrochemical stability. The ionic structure was analyzed by 27Al nuclear magnetic resonance; Raman spectroscopy and the dissolution phenomenon was studied by ultraviolet-visible spectroscopy. The dissolution mechanism of NdCl3 in this solvate ionic liquid was derived as 3[AlCl2(EC)n]+ + 2NdCl3 ⇆ 2Nd(III) + 3[AlCl4]− + 3nEC. Cyclic voltammetry was used to explore the electrochemical behavior of Nd- and Al-containing species, revealing that the reduction of Al and Nd are both one-step electron-gaining processes. X-ray diffraction confirmed that an Al-Nd alloy can be obtained in the form of thermally stable Al2Nd by potentiostatic electrolysis at high cathode overpotential (− 3.5 V vs. Al). Although the deposited alloy layer is not dense, Al-containing solvate ILs have immense potential in green electrometallurgy because of their higher tunability and similar properties to ILs.

Electrochemical co-deposition synthesis of Au-ZrO2-graphene nanocomposite for a nonenzymatic methyl parathion sensor

For the first time, a simple electrochemical co-deposition was utilized to synthesis the gold and zirconia nanocomposites modified graphene nanosheets on glassy carbon electrode (Au-ZrO2-GNs/GCE) for electrocatalytic analysis of methyl parathion (MP). According to Field-Emission Scanning Electron Microscopy (FE-SEM), Transmission Electronic Microscopy (TEM) and X-Ray Diffraction (XRD), the gold nanoparticles were uniformly distributed on the surface of graphene-based nanocomposite. The Au-ZrO2-GNs/GCE based sensor exhibited superior capacity for MP detection, ascribed to the strong affinity of zirconia towards the phosphoric group, as well as the high catalytic activity and good conductivity of Au-GNs. The best fabrication and work conditions were then obtained by systematically optimization of the electrodeposition process, pH value and enrichment time. Compared to the gold nanoparticles, zirconia or graphene modified electrodes, AuZrO2-GNs/GCE sensor displayed superior electro-catalytic response toward MP oxidation. The sensor response current of square wave voltammetry was highly linearly correlated with the MP concentrations range of 1–100 ng mL−1 and 100–2400 ng mL−1 with the detection limit of 1 ng mL−1. The Au-ZrO2-GNs/GCE nanocomposite sensor showed excellent accuracy and reproducibility for detection of MP in Chinese cabbage samples, providing a new method for efficient pesticide detection in practical applications.

Tribological Properties of Multi-Walled Carbon Nanotube-Cr and Graphene Oxide-Cr Composite Coating

Chromium (Cr)-based coatings have been widely used to strengthen the friction reduction and wear resistance on various kinds of surface. Here, the stable aqueous dispersion of oxidized multi-walled carbon nanotube (MWCNT) and graphene oxide nanosheets (GOS) was obtained by ultrasonic oxidation treatment. Then, MWCNT-Cr and GOS-Cr composite coatings were prepared using the direct current electrochemical co-deposition process on 420 stainless steel in the electrolyte with the addition of MWCNT and GOS under different current density and temperature. The morphology, structure, hardness and tribological properties of MWCNT-Cr and GOS-Cr composite coating are comparatively studied using pure Cr coating as a baseline. The friction reduction performance of MWCNT-Cr and GOS-Cr composite coatings was improved at optimum current density and temperature. The anti-wear properties of MWCNT-Cr and GOS-Cr composite coatings were enhanced by uniform embedment of MWCNT and GOS in coatings increasing the hardness and lubricity. This study suggests that the introduction of oxidized MWCNT and GOS with good dispersion could enhance the wear resistance and friction reduction of pure Cr coating due to their excellent dispersion, mechanical, and lubricant properties.

Electrode-normal magnetic field facilitating neighbouring electrochemical bubble release from hydrophobic islets

This paper gives an experimental study on electrochemical hydrogen bubble evolution at electrode surface partially covered with hydrophobic materials under electrode-normal magnetic field. Base on the method of photoetching and electrochemical co-deposition (PECD), the electrode partially covered with nickel–polytetrafluoroethylene (Ni-PTFE) materials is prepared to generate the controlled hydrogen bubble at specified islet. The anchored bubble evolution at hydrophobic islet is observed under magnetic field. Experimental results show that the hydrogen bubble release from the hydrophobic site is relatively random. Although it is not found that the obvious influence of micro-magnetohydrodynamic convection (MMHDC) on the single bubble release from isolated hydrophobic islet, MMHDC exactly plays the role of facilitating pair of bubbles releases from neighbouring hydrophobic islands. The new developed explanation of the mechanism of MMHDC influence on electrochemical bubble release has been given based on the method of numerical simulation.

Hierarchical Mn-Co sulfide nanosheets on nickel foam by electrochemical co-deposition for high-performance pseudocapacitors

In this work, we report an electrochemical co-deposition of binary metallic manganese-cobalt sulfides with tailored molar ratio of Mn and Co ions on Ni-foam substrates, which show 3-dimensinal (3D) hierarchical porous structure. Benefiting from synergistic effect and dual energy storage mechanism of manganese sulfide and cobalt sulfide, the optimal hierarchical Mn-Co sulfide nanosheet electrode exhibits areal capacitance ~ 1.724 F cm−2 at current density 1 mA cm−2 and excellent capacitance stability (65.15% capacitance retention at the current density of 5 mA cm−2 after 5000 cycles). The superior electrochemical performance might be attributed to highly conductive, 3D mesoporous framework of Ni foam, resulting in fast electron and ion transport from the electroactive materials to current collector as well as large amount of active sites. Furthermore, an asymmetric supercapacitor is also assembled, delivering an energy density of 27.6 Wh kg−1 at a power density of 645.2 W kg−1. The excellent electrochemical performance of the binder-free Mn-Co sulfide electrodes renders them as a promising electrode material for supercapacitors.

Constructing a Green Light Photodetector on Inorganic/Organic Semiconductor Homogeneous Hybrid Nanowire Arrays with Remarkably Enhanced Photoelectric Response.

We demonstrate that a novel photodetector is constructed by CdS/poly( p-phenylene vinylene) (PPV) homogeneous hybrid nanowire arrays via a simple template-assisted electrochemical codeposition approach. Owing to the well-matched energy levels between CdS and PPV, the recombination of photogenerated electrons and holes in CdS/PPV hybrid nanowire arrays is greatly inhibited. It is found that the homogeneous hybrid nanowire arrays exhibit remarkably enhanced photoelectric response and the ON/OFF ratio by 17 times compared to the individual CdS component. More importantly, the CdS/PPV hybrid nanowire arrays are observed with significant spectral selectivity especially for green light under 545 nm. In addition, a straight linear relationship is obtained between the ON/OFF ratios and the illumination intensities, implying that the quantitative detection of illumination intensity can be achieved. The new as-prepared homogeneous hybrid organic/inorganic semiconductor nanowire arrays have a bright prospect for applications in high-sensitivity and high-speed green photodetectors.

Porous nanorods of nickel–cobalt double hydroxide prepared by electrochemical co-deposition for high-performance supercapacitors

Nickel-cobalt double hydroxides (Ni-Co DHs) combined with cost-effectively commercial expanded graphite (EG) was prepared via a facile in-situ electrodeposition in mixed solvents of N,N-dimethylformamide and water. By simply adjust molar ratios of Ni2+/Co2+, a Ni-Co DHs/EG electrode in which Ni-Co DHs showing a porous-nanorod microstructure was fabricated. Thanks to synergistic effects between Ni(OH)2 and Co(OH)2 as well as the unique morphology of porous nanorods, an optimal Ni-Co DHs/EG electrode with a total mass loading of 4.0 mg cm−2 can deliver a specific capacitance of 1246 F g−1 at 1 A g−1, a rate capability of 91.8% as the discharging current density increasing from 1 to 10 A g−1, and a capacitance retention of 80.1% after 1000 cycles charged/discharged at 10 A g−1. Thus we can draw a conclusion that the Ni-Co DHs/EG electrode possesses a satisfactory specific capacitance, extremely superior rate performance, and good cycle stability, therefore it can be very competitive for practical applications in supercapacitors.

Preparation process of magnesium alloys by complex salt dehydration-electrochemical codeposition

ABSTRACTHigh-purity anhydrous MgCl2-containing molten salt was directly synthesized from MgCl2 · 6H2O via complex salts dehydration and protection. After that, Mg-Al and Mg-Zn alloys were prepared by electrochemical codeposition. The hydrolysis processes of magnesium chloride hexahydrate in various chloride mixtures were studied. Then, the preparation process was studied and the dehydration mechanism was put forward. NH4Cl·MgCl2·nH2O formed under 300°C inhibits the formation of hydrolysate during the dehydration process. KMgCl3 and K3NaMgCl6 formed above 400°C can further protect the unstable anhydrous MgCl2. Therefore, high-purity anhydrous MgCl2-containing molten salt with w(MgO)/w(MgCl2) being 0.016 wt.% was obtained. The current efficiency was above 81% and 97%, respectively, when preparing Mg-Al alloys and Mg-Zn alloys, and the alloying elements were distributed homogeneously in the alloy matrix.

Enhancement of Thermoelectric Properties of Bismuth Telluride Composite with Gold Nano-Particles Inclusions Using Electrochemical Co-Deposition

In order to enhance the figure of merit ZT, gold nano-particles-bismuth telluride composites have been synthesized using the electrochemical co-deposition and a significant improvement of thermoelectric properties has been achieved. The composite with 5 wt% of 5 nm-diameter gold nano-particles shows highest absolute Seebeck coefficient (∼380 μV/K), low thermal conductivity (∼0.5 W/m·K) and high figure of merit ZT (∼0.62) at room temperature. This ZT value is approximately forty times better than that of the as-deposited pure bismuth telluride film synthesized using the electrochemical deposition with the similar condition.

Localized Electrochemical Co-deposition of Copper-Nickel using Liquid Marbles

Localized Electrochemical Co-deposition of Copper-Nickel using Liquid Marbles

Electrochemical Co-Deposition of Gold and Carbon Nanocapsules from a Colloidal Suspension

This paper shows the preparation of a gold suspension containing carbon nanocapsules and their co-deposition from the colloidal galvanic bath on a nickel electrode to obtain gold/nanocapsules composite coatings. The incorporation of the nanocapsules was confirmed by surface analysis and confocal microscopy. The influence of suspension preparation, nanocapsule concentration and stirring during the co-deposition was analyzed and showed that capsules strongly adhere on the surface and are coated by the gold matrix forming rounded clusters. The efficiency of the galvanostatic deposition increases in presence of capsules due to the increase in the active area and the metal growth on the carbon surfaces. The results establish a theoretical background for the electrochemical co-deposition of carbon nanocapsules acting as carriers for the further development of smart coatings.

Electrodeposited Nanoporous Polypyrrole Layers for Controlled Drug Release

Nanostructured layers for controlled drug release are fabricated via direct electrochemical codeposition of polymethylmethacrylate (PMMA) nanospheres (NSs) with polypyrrole (PPy). After codeposition, NSs are etched from the matrix to leave a nanoporous PPy layer. Concentration of NSs in the composite, and the resulting concentration of porosities in the etched layer, is optimized varying deposition current density. A maximum concentration of NSs of about 49% vol., corresponding to a loose random sphere packing, is obtained. Complete dissolution of PMMA NSs upon exposure to a mixture of two solvents is demonstrated. Nanoporous layers are loaded with rhodamine B to check their drug release behavior, which is compared with corresponding bulk PPy layers. Nanoporous coatings covered with a bulk PPy capping layer show a 77% improvement in released Rhodamine B with respect to non-nanostructured PPy.

A Glance of the Electrochemical Co-Deposition of Indium and Arsenic in a Choline Chloride/Ethylene Glycol Deep Eutectic Solvent

The electrochemical behavior of arsenic(III) and indium(III) is investigated in the ethaline deep eutectic solvent (a mixture of 1 mol eq. of choline chloride and 2 mol eq. of ethylene glycol) using As2O3 and InCl3 as precursors. Cyclic voltammetry of ethaline solutions containing individual As(III) and In(III) reveals that the thermodynamic deposition potential of As is more negative than that of In in ethaline, in contrast to what has been observed in aqueous solutions. When In(III) is mixed with As(III), the reduction of In(III) shifts positively while the reduction of As(III) shifts negatively with respect to that of individual solutions. Co-deposition of In-As is attempted using potentiostatic electrolysis on Cu and Ni substrates, respectively. The electrodeposited films are characterized with scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS) and X-ray powder diffraction (XRD). The As/In atom ratio in the obtained deposits increases as the deposition potential gets more negative. Crystalline InAs film can be obtained from the ethaline solution contains a As(III) concentration higher than that of In(III). However, the co-deposits turn into amorphous once the As content in the deposits exceeds that of In.

HBMP-2 Contained Composite Coatings on Titanium Mesh Surface: Preparation and hBMP-2 Release.

Titanate nanofibers were prepared on titanium mesh by alkali-heat treatment, and calcium phosphate coating was fabricated on the porous titanate nanofibers by electrochemical deposition technology. Then hBMP-2 was introduced into the coating by different methods to improve its osteointegration and bioactivity. Three kinds of composite coatings modified by hBMP-2 were prepared (TmhB, TmHedhB and TmHhBed). Surface morphology, chemical composition, phase composition and hBMP-2 amounts and hBMP-2 release performance of the composite coatings were characterized by SEM, ATR-FTIR, XRD, and hBMP-2 ELISA kit, respectively. Results showed that all of the coatings display porous fiber structure, calcium phosphate phase in TmHedhB and TmHhBed samples was hydroxyapatite (HA), and bead-like HA particles formed on the surface of titanate nanofibers. Protein adsorption experiments showed that introduction of bead-like HA phase increased the hBMP-2 adsorption on the composite coatings, and composite coatings prepared by electrochemical co-deposition technique further enhanced hBMP-2 adsorption up to 886 ng/mg, which were supported hBMP-2 sustained release within 6-48 h.

Electrochemical Deposition of Gold Nanoparticles on Reduced Graphene Oxide by Fast Scan Cyclic Voltammetry for the Sensitive Determination of As(III).

In this study, a stable, sensitive electrochemical sensor was fabricated by the electrochemical codeposition of reduced graphene oxide (rGO) and gold nanoparticles on a glassy carbon electrode (rGO-Aunano/GCE) using cyclic voltammetry (CV), which enabled a simple and controllable electrode modification strategy for the determination of trace As(III) by square wave anodic stripping voltammetry (SWASV). SWASV, CV, electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the electrochemical properties and morphology of the proposed sensing platform. The number of sweep segments, the deposition potential and the deposition time were optimized to obtain ideal sensitivity. The presence of rGO from the electroreduction of graphene oxide on the sensing interface effectively enlarged the specific surface area and consequently improved the preconcentration capacity for As(III). The rGO-Aunano/GCE sensor exhibited outstanding detection performance for As(III) due to the combined effect of Aunano and rGO formed during the electroreduction process. Under the optimized conditions, a linear range from 13.375 × 10−9 to 668.75 × 10−9 mol/L (1.0 to 50.0 μg/L) was obtained with a detection limit of 1.07 × 10−9 mol/L (0.08 μg/L) (S/N = 3). The reproducibility and reliability of the rGO-Aunano/GCE sensor were also verified by performing 8 repetitive measurements. Finally, the rGO-Aunano/GCE sensor was used for the analysis of real samples with satisfactory results.

Carbon nanotubes sheathed in lead for the oxygen evolution in zinc electrowinning

Oxygen evolution in harsh high acidic condition is a challenge to both zinc electrowinning and hydrogen production. In the present work, the carbon nanotubes (CNTs) sheathed in lead hybrid anode has been fabricated through electrochemical codeposition, and its electrochemical performances under zinc electrowinning condition have been discussed extensively. It is also the first time to coat CNTs by Pb with tunable method via metal oxide. The CNTs/Pb composite anode shows ten times larger exchange current density and electrochemically active surface areas (ECSA) than those of pure Pb, which indicates an extra high electro-catalytic activity. The lower overpotential and polarization resistance of the CNTs/Pb composite anode for oxygen evolution are due to integrity for efficient charge transport between matrix and PbO2 by penetrating through PbO layer. Under industrial condition of current density 500 A m−2, the overpotential can be decreased by about 120 mV compared with pure Pb during the long-term durability test. Moreover, the hybrid anode comprising ~ 0.6 wt% CNTs is also cost effective. The CNTs/Pb composite anode can be a promising and cost-effective anode in harsh high acidic condition and potentially applied in zinc electrowinning practice due to high hardness and scalable production.

Effect of current density and deposition time on microstructure and corrosion resistance of Ni-W/TiN nanocomposite coating

Ni-W/TiN nanocomposite coatings were successfully prepared via pulse electroplating from an electrolyte containing suspended TiN nanoparticles. The effects of applied current density and deposition time on microstructure, morphology, composition, hardness and electrochemical behaviors of the obtained coatings were investigated. Results showed that the current density and deposition time affect remarkably the electrochemical co-deposition process and then the structure and characteristics of the composites. It illustrated that the nanocomposites are uniform, compact and crack-free. The nanocomposites prepared at Ia = 3 A dm−2 and t = 20 min had the finest structure, showing a fine and smooth surface. EDS mapping and XPS spectra illustrated that the TiN nanoparticles had been homogeneously dispersed throughout the coating. 2.34 wt% TiN nanoparticles were embedded in Ni–W (68.56 wt% Ni and 29.1 wt% W) alloy matrix at Ia= 3.0 A dm−2. The inclusion of TiN nanoparticles in Ni–W could promote the nucleation and cause a distinct microstructural change. The crystallite size was in the range of 11–15 nm. The average roughness value (Ra) is 65.7 nm and 73.8 nm for coating formed at 20 min and 40 min, respectively. The electrochemical measurements illustrated that Ia = 3–5 A dm−2 and t = 40–60 min was the optimal operating parameters for the excellent anti-corrosion properties of Ni–W/TiN nanocomposites. The embedded TiN in Ni–W matrix could fill defects then improve its corrosion resistance. This electrodeposited Ni–W/TiN nanocomposites possess excellent hardness and superior corrosion resistance, and is expected to be applied in aggressive environment as a protective coating.