Nickel Substrate Research Articles

Molecular dynamic study of the applicability of silicene lithium ion battery anodes: A review

Lithium-ion batteries (LIBs) are the main energy storage devices that have found wide application in the electrical, electronics, automotive and even aerospace industries. In practical applications, silicene has been put forward as an active anode material for LIBs. This is facilitated by its high theoretical capacitance, strength, and small volume change during lithiation. Thin-film materials containing two-layer silicene and intended for use in the LIB anode have been studied by the method of classical molecular dynamics. Among the important characteristics obtained is the fillability of the silicene anode (under the influence of an electric field), which was determined depending on the type of vacancy defects in silicene and the type of substrate used. Both metallic (Ag, Ni, Cu, Al) and non-metallic (graphite, silicon carbide) substrates are considered. The behavior of the self-diffusion coefficient of intercalated lithium atoms in a silicene channel as it is filled has been studied. Based on the construction of Voronoi polyhedra, the packing of lithium atoms and the state of the walls in the channel has been studied in detail. The change in the shape of silicene sheets, as well as the stresses in them caused by lithium intercalation, are analyzed. It has been established that two-layer silicene with monovacancies on a nickel substrate is the most optimum variant of the anode material. The results of this work may be useful in the development of new anode materials for new generation LIBs.

Computer simulation of obtaining thin films of silicon carbide.

Silicon carbide films are potential candidates for the development of microsystems with harsh environmental conditions. In this work, the production of high-purity silicon carbide films by the electrolytic method is reproduced in a computer model. Single-layer SiC films were deposited on nickel, copper, and graphite substrates. The kinetic and structural characteristics related to the Si and C atoms in this compound are presented. The coefficient of self-diffusion of C atoms on all substrates is higher than that of Si atoms. In addition, the diffusion of atoms on a graphite substrate occurs much more intensively than on metallic (Ni and Cu) substrates. The first maximum of the radial distribution function g(r)SiC is at a shorter distance when the film is deposited on the graphite substrate. A detailed analysis of the structure, based on the construction of Voronoi polyhedra, indicates that the degree of crystallinity of the film increases when changing the substrate in the order from nickel to graphite. The resulting SiC films are subject to local stresses, the strongest of which appear on the copper substrate, however the average stresses in the film do not appear to be high.

Facile method to activate substrate for oxygen evolution by a galvanic-cell reaction.

NiFe layered double hydroxide (NiFe LDH) is a promising material with multiple functions. In this communication, a novel method is used to prepare NiFe LDH. This synthesis method is achieved via galvanic-cell corrosion between nickel and iron substrates in aqueous solutions containing a halogen group anion (e.g., Cl) at ambient temperature. The as-prepared NiFe LDH electrodes are developed as electrocatalysts for the oxygen evolution reaction (OER) and exhibit excellent catalytic activities and durability. This work provides an energy-efficient, cost-effective, and scaled-up corrosion engineering approach for manufacturing NiFe LDH materials.

INVESTIGATION OF ELECTROCATALYTIC ACTIVITY OF Ni–Mo THIN FILMS FOR WATER ELECTROLYSIS

The paper presents data on the study of the electrocatalytic properties of Ni–Mo thin films in neutral and alkaline media, obtained as a result of electrochemical synthesis. Comparative characteristics of the electrocatalytic properties of deposited Ni-Mo films on various substrates and different compositions with the catalytic activity of Ni, Pt and St-3 were determined by the method of recording linear polarization curves and determining the slope of the Tafel curves. The highest catalytic activity was exhibited by Ni73.5Mo13.3O13.2 thin films on a nickel substrate that were not annealed. The dependence of the microhardness of the films on their composition was determined, and Ni–Mo films with a Mo content of 38% had the highest microhardness. It has been established that the corrosion resistance of films depends on the content of molybdenum in them, and an increase in its content in alloys increases their corrosion resistance, but the catalytic activity of the films decreases

Facile fabrication, structural and electrical investigations of cadmium sulfide nanoparticles for fuel cell performance

In the present work, CdS nanoparticles were synthesized and analyzed for use in fuel cell applications. The X-ray diffraction investigation showed that CdS possesses a cubic polycrystalline structure. For the (111) plane, the average values of mean crystallite size, microstrain, and dislocation density were calculated and found to be 1.935 nm, 0.0758, and 0.267 nm−2. The average crystallite size was additionally calculated and found to be 2.02 nm using the modified Scherrer’s plot. The observed blue shift in the photoluminescence of CdS is caused by the quantum size impact of the nanocrystalline structure. A broad emission band at 590 nm is produced by the recombination of a hole in the valence band of CdS with an electron confined in a sulfur vacancy. The average Cd/S ratio is good and comparable, according to the EDS analysis, which is close to the theoretical values and almost exactly fits the ideal structure. A thermogravimetry diagram was used to establish the thermal stability of CdS across a wide range of temperatures. Fuel cell application features peaks were investigated by the cyclic voltammetry of CdS under various conditions. The linear sweep voltammetry was used to analyze the electrochemical performance of CdS electrodes in fuel cells. Electrochemical impedance spectroscopy (EIS) was also used and the results confirmed that nickel substrate is regarded as being superior to stainless steel in terms of performance.

Effects of an epitaxial graphene layer for the growth of nickel silicides on a Ni(111) substrate

In this paper, we report on an in-depth study on the growth of nickel silicides, either on a clean Ni(111) substrate or in the presence of a previously-grown epitaxial single graphene (Gr) layer, by means of Auger electron spectroscopy (AES), low energy electron diffraction (LEED), and scanning tunneling microscopy (STM). We demonstrate that two different nickel silicides, namely Ni3Si and Ni2Si, progressively form as the annealing temperature is increased from 450 °C to 600 °C. The presence of the Gr layer does not change the nature of the two silicide phases but rather affects the morphology of the silicide overlayer. Indeed, in the presence of Gr, the deposited silicon atoms intercalate by passing through the Gr defects or domain boundaries and accumulate on specific sample areas, resulting in the formation of multilayer silicide islands. In the absence of Gr, the deposited silicon atoms react uniformly with the nickel substrate, resulting in the formation of homogeneous large scale silicide layers.

Strengthening Analysis of Ni-Sn Alloy Layer by Double Alloying Method Combined with First-Principles Calculation.

Surface modification improves the performance of materials in practical applications. In this paper, mechanical alloying pretreatment is adopted. Advanced non-equilibrium processing of a high-current pulse electron beam is then used to obtain an Sn-rich Ni-Sn alloy layer, characterized by a higher surface hardness than the initial pure nickel layer. In addition, the atomic structure of the Sn-doped nickel substrate in the alloy layer is simulated, and the improvement of the alloy layer is analyzed based on the first principle. Mechanical alloying and electron beam irradiation form fine and even nanocrystals on the surface of the nickel. Sn doping is also important for enlarging the lattice and increasing the stress.

Electronic Structure Engineering of Highly-Scalable Earth-Abundant Multi-Synergized Electrocatalyst for Exceptional Overall Water Splitting in Neutral Medium.

Efficient neutral water splitting may represent in future a sustainable solution to unconstrained energy requirements, but yet necessitates the development of innovative avenues for achieving the currently unmet required performances. Herein, a novel paradigm based on the combination of electronic structure engineering and surface morphology tuning of earth-abundant 3D-hierarchical binder-free electrocatalysts is demonstrated, via a scalable single-step thermal transformation of nickel substrates under sulfur environment. A temporal-evolution of the resulting 3D-nanostructured substrates is performed for the intentional enhancement of non-abundant highly-catalytic Ni3+ and pSn 2- species on the catalyst surface, concomitantly accompanied with densification of the hierarchical catalyst morphology. Remarkably, the finely engineered NiSx catalyst synthesized via thermal-evolution for 24h (NiSx -24h) exhibits an exceptionally low cell voltage of 1.59V (lower than Pt/C-IrO2 catalytic couple) for neutral water splitting, which represents the lowest value ever reported. The enhanced performance of NiSx -24h is a multi-synergized consequence of the simultaneous enrichment of oxygen and hydrogen evolution reaction catalyzing species, accompanied by an optimum electrocatalytic surface area and intrinsic high conductivity. Overall, this innovative work opens a route to engineering the active material's electronic structure/morphology, demonstrating novel Ni3+ /pSn 2- -enriched NiSx catalysts which surpass state-of-the-art materials for neutral water splitting.

Spectroscopic investigation of improved corrosion resistance of nickel due to multilayer graphene coating developed with suitably tilted substrate during CVD

The great variability (from remarkable to little) in graphene's ability as a corrosion barrier coating is attributed to the extent of defects and non-uniformity of graphene. This study established the theoretical basis for tailoring the orientation of the metallic substrate with respect to the direction of flow of the incoming precursor gas into the reactor during the chemical vapour deposition (CVD) of uniform graphene film on the substrate. We validated the theoretical basis by demonstration of development of a multilayer graphene coating with considerably improved uniformity and low defect content on a suitably tilted nickel substrate during CVD that provided an effective and durable corrosion resistance to the metal in an aggressive acidic medium. Thorough scanning X-ray photoemission microscopy (SPEM) using synchrotron radiation and Raman spectroscopy enabled the mechanistic understanding of the improved uniformity and low defect content of graphene coating, and their role in considerably improving the corrosion resistance of nickel.

The Mg2NiH4 film on nickel substrate: synthesis, properties and kinetics of formation

We studied the synthesis reaction of Mg2NiH4 hydride films when a nickel plate and magnesium hydride powder interacted in the presence of hydrogen at 450 °C. The hydrogen pressure (>6 MPa) was higher than the synthesis equilibrium pressure for both Mg2NiH4 and MgH2 hydrides.Film examination with scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and thermal desorption spectroscopy methods revealed that a dense polycrystalline film of Mg2NiH4 hydride grows on a thin (0.9 μm) underlayer of intermetallic alloy MgNi2. The synthesis time variation made it possible to create Mg2NiH4 films with a width of 0.2 to 4 μm. Based on analysis of the growth kinetics, the crystal structure of the material, and energies of chemical bonds between atoms, we show that the interface between MgNi2 and Mg2NiH4 is the most probable location of the growth reaction.We have obtained cathode luminescence spectra of the Mg2NiH4 hydride film. Mg2NiH4 is found to be an indirect gap semiconductor with a gap value of ∼1.6 eV. However, luminescence with quanta energy higher than the band gap is registered. We associate this fact with Van Hove singularities in the Mg2NiH4 density of states.

Comparison of electrochemical characteristics of NiCo2O4 and NiCo2S4 nanostructures for supercapacitors

This paper presents the results on the synthesis and study of the properties of NiCo2O4 and NiCo2S4 nanostructures obtained by hydrothermal synthesis for their use as supercapacitor electrodes. A method is developed for growing a nanostructure from a ternary metal oxide NiCo2O4 on a nickel substrate. The structural features of the synthesized NiCo2O4and NiCo2S4 nanostructures are studied using X-ray phase analysis. The obtained samples have a cubic modification NiCo2O4 and NiCo2S4. The data on the morphology of the synthesized samples obtained by scanning electron microscopy are presented. The samples are in the form of nanoneedles and nanowires grown on a nickel substrate. Methods for the synthesis of NiCo2O4 nanostructures have been studied, optimal conditions for the growth of nanostructures from NiCo2O4 have been determined, and a NiCo2O4 sulfurization method has been developed to obtain a NiCo2O4 nanostructure. Comparative studies have been carried out on the effects of sulfurization on the electrochemical characteristics of the obtained electrodes. It is found that, despite the fact that NiCo2O4 oxide nanostructures have a high theoretical capacitance, the replacement of oxygen atoms by sulfur atoms increases the conductivity of the materials and leads to a further increase in the specific capacitance of the end electrodes. The maximum Cs obtained specific capacitance for NiCo2S4 is 1976 F g-1 and while for NiCo2O4 it is 413 F g-1 at a scan rate of 5 mV/s. The results of the dependence of the specific capacitance on the scanning speed during measurements are also presented.

Electrochemically embedded nickel oxide in a highly porous manganese oxide film with enhanced catalytic kinetics of the urea oxidation reaction

The use of well-dispersed nickel catalysts with atomic-scale sizes is an effective approach for maximizing catalytic activity and selectivity for the urea oxidation reaction (UOR). Herein, a porous ultrathin film of Birnessite-type manganese oxide is anodically deposited on a nickel substrate as a catalyst support. Some of the intercalated sodium ions are replaced by the dissolved nickel ions from the nickel substrate in the anodic process, forming manganese oxide with partially intercalated nickel ions (denoted MnO2). The amount of nickel species can be easily increased by cyclic voltammetry in the nickel sulfate electrolyte (denoted MnO2-Ni), without the relatively time-consuming process of conventional ion exchange. Most of the embedded nickel species are catalytic Ni3+ ions, rendering MnO2-Ni a favorable catalyst to boost the UOR. The cyclic voltammetry results reveal that Ni3+ catalysts, when inserted into the layer-structured manganese oxide, can increase the electroactive surface area for the adsorption of urea and increase the charge-transfer rate constant for the Ni3+/Ni2+ redox couple, leading to an improved catalytic rate constant of the UOR. A highly porous manganese oxide matrix provides many transport pathways for facilitating UOR kinetics. Electrochemical impedance spectroscopy shows that MnO2-Ni has lower direct and indirect UOR impedances than MnO2 and bare Ni electrodes, leading to a greater oxidation current and lower onset potential.

High current water electrolysis catalyst based on Fe/Ni(Ni/Fe) hierarchically structured electrode

Developing highly active bifunctional electrodes based on low-cost transitional metals is the most promising strategy to achieve the large-scale hydrogen production via water electrolysis using the powers generated from renewable sources. In this study, a self-supported and hierarchal structured electrode based on nickel and iron is developed as a bifunctional electrode for water electrolysis, and find that the interaction between the substrate and the active material play an important role in the obtained electrocatalytic performance. The effect of the iron-nickel hierarchal structure on the catalytic activity of hydrogen evolution reaction and oxygen evolution reaction was investigated. The results show that a large operating current density for water electrolysis is achieved when iron as an active component is supported on the nickel substrate to form a hierarchically structured electrode on the surface.

Nano-and micro-engineered vertical graphene/Ni for superior optical absorption

Black coatings benefit from low reflectance or high light absorption are utilized in multifarious optical applications. Due to their unique three-dimensional nanostructure and π-band optical transitions, vertical graphene (VG) has drawn great attention to the field of black coatings. However, how the morphology of VGs affects reflectance has not been comprehensively disclosed yet. In addition, the morphology of the substrate for VG growth also affects the absorption properties. Here, we report a nano-and micro-engineered VG/Ni structure based on VG and laser-modified nickel foil, which possesses omnidirectional low reflectance of ∼0.25% over the visible range. A larger spacing of graphene nanowalls is more conducive to the formation of light traps and improves the absorption property. Besides, the surface of nickel substrate by laser irradiation presents a “cauliflower-like” microstructure, which further enhances light-trapping ability.

Electrodeposition of binderless Ni,Zn-MOF on porous nickel substrate for high-efficiency supercapacitors

In this article, an indirect electrodeposition technique is applied for developing single- and bimetal-MOFs onto a porous nickel-foam (NF) support, which is found to have significant applications in a supercapacitor as binderless electrodes. In this regard, Ni-, Zn- and Ni,Zn-MOFs with different morphologies were deposited onto NF electrodes through indirect cathodic electrochemical deposition from terephthalic acid dissolved metal nitrate aqueous solutions. The prepared MOFs were analyzed using XRD, FT-IR, SEM and EDS analyzes. The structural analyses proved the formation of crystalline Ni-, Zn- and Ni,Zn-bdc MOFs onto nickel foam support. Electrochemical evaluations by charge-discharge tests revealed that the fabricated Ni-BDC/Ni foam, Zn-BDC/Ni foam and Ni,Zn-BDC/Ni foam electrodes are respectively capable of delivering specific capacitances of 536, 374, and 944 ​F ​g–1 at the applied current load of 2 ​A ​g–1. Furthermore, it is found that our fabricated samples exhibit capacitance retentions of 75.5%, 84.95% and 93.24% during 6000 cycling with the current density of 5 ​A ​g–1, respectively. The proper charge storage ability of the Ni,Zn-BDC/Ni foam electrode is attributed to its appropriate surface morphology, synergism effects and excellent physical contact as well as proper self-assembling onto the Ni foam.

3D substrate self-sacrifice Ni2P integrated anode for high-performance sodium-ion battery

Carbon-coated 3D self-growing Ni2P were prepared on the foamed nickel substrate by hydrothermal activation combined with carbonization and phosphating strategy. The crystal structure and elemental composition of the samples were obtained by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while the microscopic morphology and crystallographic information of the materials were obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that uniform carbon-coated Ni2P was successfully self-grown on the smooth three-dimensional nickel foam substrate. Meanwhile, the investigation results of energy storage capacity show that the synthesized anode material exhibits excellent sodium storage specific capacity and rate performance. After more than 100 cycles of galvanostatic charge and discharge at a current density of 100 mA.g−1, as-synthesized material still maintains a reversible specific capacity of over 300 mAh.g−1. In addition, the pseudocapacitive behavior of the electrode was judged by kinetic calculation, and then the contribution rate of the pseudocapacitive behavior to the charge storage was calculated. Apparent activation energy, sodium ion diffusion coefficient and diffusion apparent activation energy were used to analyze the rapid reaction kinetics of materials with diffusion-controlled battery behavior.

Self-supporting one-dimensional ZnFe-BDC for electrocatalysis oxygen evolution reaction in alkaline and natural seawater

The morphology and overall electronic structure of the metal-organic framework (MOF) can be regulated by introducing non-noble metal elements so that it has higher electrocatalytic oxygen evolution reaction (OER) activity but does not change the stability of MOF itself. Herein, we report a series of self-supporting ZnFe bimetallic MOF electrocatalysts on foam nickel (NF) substrates using a simple one-step solvothermal strategy. The morphology evolution process and electronic structure of the Zn2+/Fe3+ molar ratio from 0.25 to 0.75 are systematically investigated. It is worth noting that the overpotentials of ZnFe-BDC-0.75 in alkaline freshwater electrolyte and natural seawater electrolyte are 292 mV and 308 mV (100 mA cm−2), respectively. This work emphasizes the significance of tailoring the electronic microstructure of bimetallic MOFs for efficient OER activity in alkaline and seawater.

Theoretical and experimental investigation of electrical double layer capacitance of LiClO4-interacted metal substrates and carbon-coated nickel electrode

ABSTRACT Suitable transitional metal electrode substrate should keep high electroactivity and meanwhile suppress polarization effect. Theoretical calculation and experimental measurement are adopted to investigate interfacial interaction-dependent capacitance of lithium perchlorate-titanium and nickel (LiClO4-Ti, LiClO4-Ni) metal substrates. LiClO4-Ti reveals ideal electrical double layer capacitance due to electrochemical stability and LiClO4-Ni reveals the deviated electrical double layer capacitance due to polarization effect in potential range of 0–0.8 V. LiClO4-Ni reveals lower ohmic resistance, charge transfer resistance and Warburg resistance to present higher conductivity, more active interface, and more feasible ion diffusion properties than LiClO4-Ti. Titanium and nickel substrates achieve mean response current of 0.13–2.47 μA cm−2 and 1.03–22.20 μA cm−2 at 5200 mV s−1. The corresponding specific capacitances are 0.010–0.0095 mF cm−2 and 0.322–0.155 mF cm−2 at 0.01–0.10 mA cm−2. LiClO4-Ni keeps much higher capacitance but relatively lower electrochemical stability than LiClO4-Ti. Theoretical calculation proves interfacial electrostatic adsorption of LiClO4 on Ti and Ni substrates could change charge density distribution. LiClO4-Ni with the enlarged potential difference causes intensified polarization effect. LiClO4-Ni exhibits higher electrical conductivity and lower interface energy than LiClO4-Ti. Furthermore, carbon-coated nickel (C@Ni) was prepared to mostly restrain polarization effect and meanwhile keep high electroactivity of Ni substrate for the promising supercapacitor electrode application. It reveals specific capacitance of 25.9 mF cm−2 and cycling capacitance retention of 94.5% after 1000 charge-discharge cycles at 1.0 mA cm−2 in 1.0 M LiClO4. The C@Ni electrode accordingly exhibits superior electroactivity and electrical double layer capacitance for energy storage application.

Enhanced electrocatalysis of 3 D structured array electrodes for energy-efficient hydrogen production by a negative thermal expansion film

Temperature is extremely significant for electrocatalysis, but heat will cause deformation and failure of catalysts. To intensify reaction and decrease thermal deformation for hydrogen production, Ni3S2 nanorods (NS NRs) arrays were prepared by electrochemical co-deposition, dealloying and vulcanization, and further covered with a film of a negative thermal expansion (NTE) material of Al2(WO4)3 via a facile deposition method to obtain rod@shell three-dimensional (3 D) structured Ni3S2@Al2(WO4)3 (NSAW) NRs catalysts which connect a nickel substrate without binder. The physicochemical properties and electrocatalytic performance of the as-obtained NRs were evaluated using various techniques, and the enhanced mechanism was proposed based on multifarious results under different conditions. The hydrogen production rate of NSAW is increased 61% as temperature increases from 25 to 95 °C. Compared to the NS NRs, the hydrogen evolution reaction (HER) overpotential at 10 mA/cm2 is reduced to about 95 mV at 95 °C, and the Rct is decreased 84.7%, while the Faraday current efficiency is improved to 86.2%. Al2(WO4)3 protects NS well from breakdown during cycles in heating circumstances to improve catalytic performance and long-term stability. The work supplies an effective strategy to enhance the performance of catalysts at high temperature.

Ultrafast and Eco-Friendly Fabrication Process for Robust, Repairable Superhydrophobic Metallic Surfaces with Tunable Water Adhesion.

Superhydrophobic metallic surfaces with a water contact angle greater than 150° have attracted considerable attention in both fundamental research and industrial applications due to their special properties such as antibiofouling, drag reduction, self-cleaning, anti-icing, anticorrosion, and oil-water separation. Until now, the development of superhydrophobic practical applications is mainly limited by the process complexity, long fabrication time, coating with toxic materials, and easily damaged surface structure. To reduce the fabrication time, and simplify the process for industrial applications, an eco-friendly postprocess has been developed in this research. The superhydrophobic surfaces on the laser-textured titanium, aluminum, copper, stainless steel, and nickel substrates were fabricated extremely rapidly by a simple surface modification of only a 10 min heat treatment with nontoxic silicone oil. Hydrophobic organic group absorption has been accelerated on the silicone oil heat-treated surface and has created a low-energy surface. In addition, we demonstrated the potential of using the laser areal fluence parameter, which could be an alternative to single-laser process parameters such as scanning speed, power, and step size, to fine-tune the water adhesion behavior. Therefore, a surface that integrates different water adhesion behaviors can be easily fabricated for more complex practical applications such as controlled microdroplet transportation, microfluidic systems, and certain biomedical processes. Moreover, the robustness of superhydrophobic surfaces was confirmed by abrasion tests, knife-scratch tests, chemical durability tests, and aging tests, and their repairability was evaluated for product applications in practice.