Ternary Nickel Research Articles

Microwave synthesis of three-dimensional nickel cobalt sulfide nanosheets grown on nickel foam for high-performance asymmetric supercapacitors

A facile and cost-effective microwave method is developed to prepare ternary nickel cobalt sulfide (NiCo2S4) interconnected nanosheet arrays on nickel foam (NF). When acting as an electrochemical supercapacitor electrode material, the as-prepared NiCo2S4/NF shows a high specific capacitance of 1502 F g−1 at a current density of 1 A g−1, and outstanding cycling stability of 91% capacitance retention after 8000 cycles. In addition, a asymmetric supercapacitor (ASC) is composed of NiCo2S4/NF as positive electrode and activated carbon as negative electrode, which exhibits a high energy density of 34.7 W h kg−1 at a power density of 750 W kg−1 and long-term cyclic stability (83.7% capacity retention after 8000 cycles). Even at a high power density of 15 kW kg−1, it still remains an energy density of 17.9 W h kg−1, which is able to light up a light-emitting diode. These findings provide a new and facile approach to fabricate high-performance electrode for supercapacitors.

Ternary nickel cobalt iron sulfides ultrathin nanosheets grown on 3-D nickel nanocone arrays‑nickel plate current collector as a binder free electrode for fabrication of highly performance supercapacitors

The design of 3-dimensional (3-D) nanostructured materials on the novel current collectors has recently considered as a promising strategy for developing high-performance supercapacitors. Herein, in the first step, a novel 3-D nickel nanocone arrays (NCAs) are synthesized on the surface of nickel plate (NP) by a one-step electrodeposition method without using any template (NCAs-NP). Then, a simple and efficient method is developed for fabricating ternary metal sulfides electrodes based on the electrodeposition of nickel cobalt iron sulfide (Ni-Co-Fe-S) ultrathin nanosheets on the surface of NCAs-NP. Taking advantages of the unique flower like structure of Ni-Co-Fe-S ultrathin nanosheets and cluster structure of the three-dimensional NCAs, the ternary metal sulfide electrode (Ni-Co-Fe-S@NCAs-NP) exhibits high specific capacitances (2159.7F/g at 7A/g and 1461F/g at 35A/g) with excellent rate capabilities. An asymmetric supercapacitor is fabricated by applying the Ni-Co-Fe-S@NCAs-NP as the positive electrode and reduced graphene oxide coated on the nickel foam (rGO-NF) as the negative electrode, renders an excellent electrochemical performance for practical applications. Our asymmetric Ni-Co-Fe-S@NCAs-NP//rGO-NF supercapacitor showed a high energy density of 35.9Whkg−1 at a power density of 375Wkg−1 and even at power density of 7500, the energy density is still as high as 6.90Whkg−1.

Construction of Hierarchical CuO/Cu₂O@NiCo₂S₄ Nanowire Arrays on Copper Foam for High Performance Supercapacitor Electrodes.

Hierarchical copper oxide @ ternary nickel cobalt sulfide (CuO/Cu2O@NiCo2S4) core-shell nanowire arrays on Cu foam have been successfully constructed by a facile two-step strategy. Vertically aligned CuO/Cu2O nanowire arrays are firstly grown on Cu foam by one-step thermal oxidation of Cu foam, followed by electrodeposition of NiCo2S4 nanosheets on the surface of CuO/Cu2O nanowires to form the CuO/Cu2O@NiCo2S4 core-shell nanostructures. Structural and morphological characterizations indicate that the average thickness of the NiCo2S4 nanosheets is ~20 nm and the diameter of CuO/Cu2O core is ~50 nm. Electrochemical properties of the hierarchical composites as integrated binder-free electrodes for supercapacitor were evaluated by various electrochemical methods. The hierarchical composite electrodes could achieve ultrahigh specific capacitance of 3.186 F cm−2 at 10 mA cm−2, good rate capability (82.06% capacitance retention at the current density from 2 to 50 mA cm−2) and excellent cycling stability, with capacitance retention of 96.73% after 2000 cycles at 10 mA cm−2. These results demonstrate the significance of optimized design and fabrication of electrode materials with more sufficient electrolyte-electrode interface, robust structural integrity and fast ion/electron transfer.

In situ construction of porous NiCo2O4/Ni foam electrodes for high-performance energy storage applications

A novel three-dimensional (3D) porous flower-like NiCo2O4 electrode is reported. The electrode is constructed by homogeneous chemical co-precipitation involving the in situ growth of ternary nickel cobaltite nanosheets on a Ni foam, and a high temperature heat treatment. Field emission electron microscopy (FESEM) demonstrate that the porous flower-like structure is made up of uniform thin nanosheets with thickness of about 10 nm. Electrochemical studies reveal that the porous flower-like electrode exhibits excellent supercapacitor behavior with a high initial specific capacitance of 1046 F g−1 (at 1 A g−1) and stable cycling performance.

Single-Step Electrodeposited Molybdenum Incorporated Nickel Sulfide Thin Films from Low-Cost Precursors as Highly Efficient Hydrogen Evolution Electrocatalysts in Acid Medium

Large-scale production of hydrogen—the energy carrier of the future—remains challenging on economy grounds. Low-cost synthetic designs are necessary to produce electrocatalysts for hydrogen evolution reaction (HER). Ternary nickel molybdenum sulfides Ni1–xMoxS (x = 0, 0.04, 0.08, 0.16) have been electrochemically grown on fluorine-doped tin oxide substrate as highly active and stable HER electrocatalysts. The merits of this method are (1) the electrochemical method is energy efficient at ambient conditions and can be easily scaled up on large surface area substrates; (2) Ni, Mo, and S precursors used for the deposition are readily available and relatively cheaper compared to similar methods; and (3) the synthesis procedure is simple, one step, and requires no further heat treatments. The deposited thin films have been examined using regular physical characterization techniques, and their HER activity has been evaluated through electrochemical methods. Ni0.96Mo0.04S, especially, has exhibited a promising H...

Ternary Ni-Co-F Nanocrystal-Based Supercapacitors.

Ternary nickel cobalt fluoride (Ni-Co-F) nanocrystals are constructed solvothermally for use as the positive electrode materials in supercapacitors. The optimal Ni-Co-F (Ni/Co=2:1) shows slight chemical shifts in X-ray diffraction (XRD) data and X-ray photoelectron spectra (XPS) compared with bare Ni-F and Co-F. The Ni-Co-F (Ni/Co=2:1) exhibits typical square nanocrystal morphology together with a mesoporous surface structure, as observed through TEM observations and nitrogen sorption measurements. Owing to the stronger synergistic effect of Ni and Co redox species originated from the richer Ni and Co surface electroactive sites, Ni-Co-F (Ni/Co=2:1) shows superior performances of specific capacitance, rate capability, and charge-transfer kinetics (564 F g-1 at 1 Ag-1 , 418 F g-1 at 16 Ag-1 , 449 Ω) compared with all the other Ni-Co-F candidates. Moreover, the activated carbon (AC)//Ni-Co-F (Ni/Co=2:1) asymmetric capacitor designed based on charge balance delivers superior energy and power densities (18.4 Wh kg-1 , 6.64 kW kg-1 ) together with longer cycle life (77 % retention after 10 000 cycles at 4 A g-1 ).

Stability constants of the ternary nickel(II) complexes with salicylic acid and selected amino acids

In this work, we present the study of the ternary Nickel(II) complexes with salicylic acid and the amino acids: aspartic acid (H2Asp, H2L), glutamic acid (H2Glu, H2L), cysteine (H2Cys, H2L) and histidine (HHis, HL) formed in aqueous solution at 25°C and 1.0mol·dm−3 NaCl as the ionic medium. The analysis of the potentiometric data by means of the computational least-squares program LETAGROP, indicate the formation of the ternary complexes [Ni(Sal)H2L]2−n, [Ni(Sal)HL]1−n, [Ni(Sal)L]−n, [Ni(Sal)L(OH)]−(1+n). Where n=1 for histidine and 2 for the other amino acids. The relative stability of the ternary complexes compared to the binary ones were evaluated considering the values of ∆log K, log X and % R.S. Species distribution diagrams as a function of pH were briefly discussed.

Sulfiphilic Nickel Phosphosulfide Enabled Li2 S Impregnation in 3D Graphene Cages for Li-S Batteries.

A 3D graphene cage with a thin layer of electrodeposited nickel phosphosulfide for Li2S impregnation, using ternary nickel phosphosulphide as a highly conductive coating layer for stabilized polysulfide chemistry, is accomplished by the combination of theoretical and experimental studies. The 3D interconnected graphene cage structure leads to high capacity, good rate capability and excellent cycling stability in a Li2S cathode.

Shape-controllable syntheses of ternary Ni-Co-Se alloy hollow microspheres as highly efficient catalytic materials for dye-sensitized solar cells

Ternary nickel cobalt selenide (Ni-Co-Se) alloy based hollow microspheres have been successfully synthesized via a simple one-step hydrothermal route by controlling different hydrothermal temperatures. The prepared samples were divided by reaction temperatures (140, 160, 180 and 200°C) and named as Ni-Co-Se-140, Ni-Co-Se-160, Ni-Co-Se-180 and Ni-Co-Se-200, respectively. With the temperature increasing, the hollow microspheres formed at the lower temperature and broke at the higher temperature, and the sample Ni-Co-Se-180 exhibited the most regular and homogeneous hollow microspheres with a size of 1.5–2.5μm. Moreover, the Ni atomic ratios in Ni-Co-Se alloys increased with the temperature rising. The prepared Ni-Co-Se alloys were used as counter electrode (CE) catalysts for dye-sensitized solar cells (DSSCs). A series of electrochemical tests all verified Ni-Co-Se alloy based CEs had superior electrocatalytic activities and Ni-Co-Se-180 CE displayed the largest current density, lowest overpotential and smallest charge-transfer resistance than the other CEs and Pt CEs. Benefiting from their unique morphologies and surface structures, the cells with the Ni-Co-Se-160, Ni-Co-Se-180 and Ni-Co-Se-200 based CEs achieved high efficiencies of 8.39%, 9.04% and 8.72%, respectively, which were all higher than that of Pt CE (8.07%).

Ternary nickel–iron sulfide microflowers as a robust electrocatalyst for bifunctional water splitting

3D ternary nickel iron sulfide microflowers with a hierarchically porous structure have been directly grown on Ni foam via a convenient two-step method for efficient bifunctional water splitting.

Nano-structured Bimetallic (Ni,Co) Sulphide Complex, Synthesis Characterization and Thin Film Deposition by PVD Assisted Technique

Transition metal sulfides have attracted great attention owing to their outstanding properties and varied applications in photovoltaic devices. Ternary nickel cobalt sulfides are materials that have been considered as good electrode material for high performance energy storage devices owing to their higher electrochemical activity and capacity as compared to mono-metal sulfides. NiCo2S4 compound has been synthesized by annealing of its respective metal diethyl dithiocarbamtes (Cobalt and Nickel) complexes. Furthermore the compound formed was characterized by UVVis absorption which reveals that C10H20NiN2S4 has λmax at 290 nm while C10H20CoN2S4 has λmax at 321 nm and NiCo2S4 at 291 nm, FTIR of cobalt diethyl dithiocarbamate showing bands at 1487cm-1 and 1064 cm-1 while nickel diethyl dithiocarbamate showing bands at 1519 cm-1 and 993 cm-1 and NiCo2S4 showing sulfide stretchings at 447 cm-1 and 619 cm-1, in XRD major peaks were at 2θ=18Eš, 24Eš, 31.5Eš, 33Eš, 41Eš) while SEM confirmed the cubic structure of crystals. All the results indicated the synthesis of crystalline nickel cobalt sulfide. Thin films of nickel cobalt sulfide were made using PVD technique and calculated band gap was found to be 2.4 eV. Thus it is suggested that compound formed is excellent material for use in supercapacitors and also as an electrode material.

Morphology-Tuned Synthesis of Nickel Cobalt Selenides as Highly Efficient Pt-Free Counter Electrode Catalysts for Dye-Sensitized Solar Cells.

In this work, morphology-tuned ternary nickel cobalt selenides based on different Ni/Co molar ratios have been synthesized via a simple precursor conversion method and used as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). The experimental facts and mechanism analysis clarified the possible growth process of product. It can be found that the electrochemical performance and structures of ternary nickel cobalt selenides can be optimized by tuning the Ni/Co molar ratio. Benefiting from the unique morphology and tunable composition, among the as-prepared metal selenides, the electrochemical measurements showed that the ternary nickel cobalt selenides exhibited a more superior electrocatalytic activity in comparison with binary Ni and Co selenides. In particular, the three-dimensional dandelion-like Ni0.33Co0.67Se microspheres delivered much higher power conversion efficiency (9.01%) than that of Pt catalyst (8.30%) under AM 1.5G irradiation.

Vertically cross-linked and porous CoNi2S4 nanosheets-decorated SiC nanowires with exceptional capacitive performance as a free-standing electrode for asymmetric supercapacitors

Abstract In this paper, a simple, low-cost and mild hydrothermal technology of growing vertically cross-linked ternary nickel cobalt sulfides nanosheets (CoNi 2 S 4 NSs) with porous characteristics on SiC nanowires (SiC NWs) supporters with outstanding resistances to oxidation and corrosion, good conductivity and large specific surface area deposited directly on carbon cloth (CC) is successfully developed, forming a new family of free-standing advanced hybrid electrode for asymmetric supercapacitors (ASCs). Such integrated electrode (SiC NWs@CoNi 2 S 4 NSs) manifests intriguing electrochemical characteristics such as high specific capacity (231.1 mA h g −1 at 2 A g −1 ) and rate capability due to the synergistic effect of SiC NWs and CoNi 2 S 4 NSs with unique morphology. Additionally, an asymmetric supercapacitor is also assembled via using this special hybrid architectures as positive electrode and activated carbon (AC) on Ni foam (NF) as negative electrode, and it can yield a high energy density of 57.8 W h kg −1 with a power density of 1.6 kW kg −1 and long cycling lifespan. This study constitutes an emerging attractive strategy to reasonably design and fabricate novel SiC NWs-based nanostructured electrodes with enhanced capacity, which holds great potential to be the candidate of electrode materials for environmentally benign as well as high-performance energy storage devices.

A novel approach to fabricating a nanotwinned surface on a ternary nickel alloy

Deformation nanotwinning is performed using molecular dynamics (MD) on a single crystal in a ternary nickel (Ni) alloy. Generalized embedded-atom method (EAM) potential functions are obtained for the ternary Ni alloy. The critical twinning stress is 4.48GPa, calculated by the MD simulations. Detwinning, restoring and regenerating of nanotwins take place during the unloading process, contributing to the remaining of the ductility. According to the MD simulations, a novel approach is proposed to fabricating a nanotwinned surface using nanoindentation at room temperature. This is different from previous reports, in which high temperature, high pressure or chemical regents are employed.

Multi-objective optimization of electroless ternary Nickel–Cobalt–Phosphorous coating using non-dominant sorting genetic algorithm-II

Study of electroless Nickel–Cobalt–Phosphorous coating was conducted on pure Copper substrate. The weight percentages of Nickel and Cobalt in the deposited mass, evaluated through energy dispersive X-ray analysis, have been selected as the response variables for statistical analysis. A response surface model with central composite design is developed to explain the effect of curvature in the predicted responses. Student’s t test has identified that concentration of Cobalt Sulfate is the significant process parameter for both the responses. The response surface plots and p-values have predicted the same. Fisher’s F test confirms that the response surface equation has excellent fitting to the observed values. A multi-objective optimization method has been employed in a quest to obtain the optimal values of process parameters, to maximize the responses. The Pareto optimal front of solutions, obtained from NSGA-II, provides more flexibility to the decision maker with the values of the optimal process parameters.

Asymmetric supercapacitors with metal-like ternary selenides and porous graphene electrodes

Asymmetric supercapacitors provide a promising approach to fabricate capacitive energy storage devices with high energy and power densities. In this work, asymmetric supercapacitors with excellent performance have been fabricated using ternary (Ni, Co)0.85Se on carbon fabric as binder-free positive electrode and porous free-standing graphene film as negative electrode. Owing to their metal-like conductivity (~1.67×106Sm−1), significant electrochemical activity, and superhydrophilic nature, our nanostructured ternary nickel cobalt selenides result in a much higher areal capacitance (2.33Fcm−2 at 4mAcm−2), better rate performance and cycling stability than their binary selenide equivalents, and other ternary oxides and chalcogenides. Those hybrid supercapacitors can afford impressive areal capacitance and stack capacitance of 529.3mFcm−2 and 6330mFcm−3 at 1mAcm−2, respectively. More impressively, our optimized asymmetric device operating at 1.8V delivers a very high stack energy density of 2.85mWhcm−3 at a stack power density of 10.76mWcm−3, as well as 85% capacitance retention after 10,000 continuous charge–discharge cycles. Even at a high stack power density of 1173mWcm−3, this device still deliveries a stack energy density of 1.19mWhcm−3, superior to most of the reported supercapacitors.

In situ growth of binder-free CNTs@Ni–Co–S nanosheets core/shell hybrids on Ni mesh for high energy density asymmetric supercapacitors

A facile two-step method has been developed to synthesize 3D core/shell-structured composites (CNTs@Ni–Co–S) composed of ternary nickel cobalt sulfide nanosheets (Ni–Co–S) as the shell and carbon nanotubes (CNTs) as the core on a flexible Ni mesh (Ni@CNTs@Ni–Co–S).

Mesoporous NiCo2O4 nanospheres with a high specific surface area as electrode materials for high-performance supercapacitors

Ternary nickel cobaltite has attracted more and more attention as a promising electrode material for high performance supercapacitors (SCs) due to its high theoretical capacity, unique crystal structure and excellent electronic conductivity.

Synthesis and electrochemical performances of Mn x Co y Ni z CO3

The hydrothermal method was used to synthesize microstructured MnxCoyNizCO3. The samples were characterized by X-ray diffraction and scanning electron microscopy. Energy-dispersive spectroscopy was used to analyze the contents of the elements in different samples. The electrochemical properties of the samples were investigated by a comprehensive battery testing system. The results showed that sample-1 (Mn0.714Co0.143Ni0.143CO3) and sample-2 (Mn0.769Co0.154Ni0.077CO3) were formed under different conditions. Both of the samples took on the morphology of microspheres with diameters between 3 and 6 μm. Electrochemical tests demonstrated that sample-1 featured better electrochemical performance than sample-2 and showed a higher reversible discharge capacity of 754 mAh g−1 after 200 cycles at the current density of 100 mA g−1 in the voltage range of 0.01–3 V. Hence, ternary manganese–nickel–cobalt carbonates with suitable composition could be used as high-capacity anode materials for lithium-ion battery application.

Cyclic degradation of titanium–tantalum high-temperature shape memory alloys — the role of dislocation activity and chemical decomposition

Titanium–tantalum shape memory alloys (SMAs) are promising candidates for actuator applications at elevated temperatures. They may even succeed in substituting ternary nickel–titanium high temperature SMAs, which are either extremely expensive or difficult to form. However, titanium–tantalum alloys show rapid functional and structural degradation under cyclic thermo-mechanical loading. The current work reveals that degradation is not only governed by the evolution of the ω-phase. Dislocation processes and chemical decomposition of the matrix at grain boundaries also play a major role.