Ni-based Compound Research Articles

A Nickel-Based Coordination Compound with Tunable Morphology for High-Performance Anode and the Lithium Storage Mechanism

Metal-organic coordination compounds (MCCs) have received a lot of attention as anodes for lithium-ion batteries (LIBs) due to their abundant structural configuration, tunable morphology, high surface area, and low cost, but the lithium storage mechanism of MCCs is still a mystery. Herein, we synthesized a kind of nickel-based coordination compound (marked as Ni-PP-x, x = 1, 2, or 3) with tunable morphologies and different solvent ratios via a microwave irradiation solvothermal method and then applied them as anodes for LIBs. Among them, the Ni-PP-2 electrode, with a hollow and urchin-like structure, showed the longest lifespan and maintained a high capacity of 713 mAh g−1 at 2.0 A g−1 after 800 cycles. Measured by ex situ X-ray photoelectron spectroscopy (XPS) and ex situ Fourier transform infrared spectroscopy (FT-IR), the Ni-PP-2 electrode was confirmed by a redox reaction mechanism of Li+ cations with a benzene ring and O-Ni2+/O-Ni0 coordination bonds, and the cyclic voltammetry curves have exhibited a capacitive dominated lithium storage behavior. This work provides a new type of Ni-based coordination compound and an in-depth understanding of their lithium storage mechanism, paving the way for the application of MCC compounds in the future.

Pressure dependence of superconducting properties of layered BaNi2P2

The discovery of unconventional superconductivity in a broad class of iron-based materials invoked extensive research on the corresponding compounds of other transition metals. For instance, BaNi2P2 exhibits a superconducting transition with a critical temperature Tc = 2.5 K, and is isostructural to the 122 families of the iron arsenides, suggesting that this Ni-based compound may be another example of unconventional superconductivity. Here we report a detailed analysis of the high-pressure behavior of the angle- and magnetic field-dependent electrical resistivity. The experimentally observed decrease of Tc under the applied pressure matches well with the theoretical prediction based on Migdal-Eliashberg theory, providing evidence in favor of a conventional nature of superconductivity in the nickel analogs of the iron superconductors.

Low-cost synthesis of non-noble Ni-based MXene (Ni3C) nanosheets decorated nickel foam as a bifunctional electrocatalyst for alkaline-acid urea-nitrate fuel cell

Urea and nitrate are the two indispensable hydrogen generation molecules present in different biological and non-biological sources like human urine, wastewater, groundwater samples. These molecules can be removed via urea oxidation reaction (UOR) and nitrate reduction reaction (NRR) while using them as a source for direct urea fuel cells (DUFCs) and direct nitrate fuel cells (DNFCs), respectively. Herein, we report the nickel-based MXene (Ni3C) nanosheets modified 3D skeletal nickel foam (Ni3C/NF) as a bifunctional catalyst electrode for DUFC and DNFC in alkaline and acid electrolytic medium, respectively. The high purity synthesis of Ni3C nanosheets is achieved through a solid-state synthesis of Ni-based MAX compound (Ni3AlC2) followed by an etching and exfoliation process (via solvothermal technique). The as-fabricated Ni3C/NF electrode exhibits a peak current density of 434 mA/cm2 (for UOR) and 85 mA/cm2 (for NRR) at an onset potential of ∼0.62 V (vs Hg/HgO) and ∼-0.58 V (vs Hg/HgO), respectively. This performance of the electrode is ascribed to the improved electrocatalytic activity of Ni3C nanosheets with good chemical stability and large surface area for UOR and NRR. This excellent bifunctional performance of the catalyst electrode proves the efficacy of the Ni3C nanosheets-based electrode for direct fuel cell applications.

Corrosive engineering assistedin situconstruction of an Fe–Ni-based compound for industrial overall water-splitting under large-current density in alkaline freshwater and seawater media

The synthesized flower-like Fe–Ni–O–N presents excellent electrocatalytic performance for OER. The assembled electrolyzer shows remarkable catalytic performance and stability in alkaline freshwater, seawater and industrial conditions (60 °C, 6 M KOH).

Ni(III) Mott-Hubbard-like State Containing High-Spin Ni(II) in a Semiconductive Bromide-Bridged Ni-Chain Compound.

Halogen-bridged linear chain metal complexes (MX-Chains) are fascinating compounds that have a quasi-one-dimensional (1D) electronic system. In this study, we synthesized the first Ni-based MX-Chain compound having hydroxy groups, i.e., [Ni(dabdOH)2Br]Br2·[Ni(dabdOHx)2Br]0.5·(2-PrOH)0.25·(MeOH)0.25 (1·solvent, x = ∼0.6, dabdOH = (2S,3S)-2,3-diaminobutane-1,4-diol). Single-crystal X-ray diffraction revealed that the MX-Chains in 1·solvent formed sheets and single-chain structures in the superlattice. It suggested an MH-like state, whereas the polarized reflection and Raman spectra suggested a CDW-like state. Magnetic and electron spin resonance measurements revealed that both high-spin Ni(II) (∼15%) and low-spin Ni(III) (∼85%) sites are present in the chain structures, i.e., the metal sites show mixed valency. Therefore, we concluded that 1·solvent adopts an intermediate state between the MH and CDW states. Moreover, a single crystal of 1·solvent exhibited semiconductive characteristics along the chain direction. This finding represents a new structural and electronic state of 1D electronic systems as well as MX-Chains.

Facile synthesis of nickel@carbon nanorod composite for simultaneously electrochemical detection of dopamine and uric acid

Nickel nanoparticles loaded with carbon nanorods (Ni@CNRs) were facile synthesized by pyrolysis of a Ni-based coordination compound. The constructed Ni@CNRs hybrid showed a high special surface area with Ni nanoparticles uniformly distributing on its surface. It is expected that the high special surface area of Ni@CNRs may increase the exposure of active sites, whereas the uniformly distribution of Ni nanoparticles may shorten the gap between Ni nanoparticles and CNRs, and then speeds up the electron migration. Then, Ni@CNRs were used as effective electrochemical sensor for simultaneous dopamine (DA) and uric acid (UA) detection. It is found that Ni@CNRs modified electrode exhibited two linear ranges of 0.5–30 μM and 35–100 μM for both single detection of DA and UA. The detection limits (S/N = 3) were calculated to be 0.056 μM for DA and 0.166 μM for UA, respectively. In addition, due to its high sensitivity and stability, Ni@CNRs was successfully applied for DA and UA analysis in human urine. These results show that Ni@CNRs is an effective electrode material for DA and UA detection. This work provides an effective strategy for exploring new electrical sensing materials.

Impact of the forming and cycling processes on the electrical and physical degradation characteristics of HfO2-based resistive switching devices

In this work, electrical and physical analysis of filamentary-type Ni/HfO2/n+-Si resistive random access memory devices were carried out with the aim of evaluating the microstructural changes occurring in the oxide layer and metal electrode after the initial forming step and subsequent switching cycles. To this end, Scanning Electron Microscopy analysis of the top oxide surface after Ni removal was performed. The obtained images show the generation of small hillocks and defects in the active area of the device caused by current-induced Joule heating effects. Material analysis of these hillocks reveals that they are a Ni-based compound. The size and morphology of the generated damage is shown to depend both on the switching polarity and compliance used to limit the current flow during the formation of the conductive filament. In addition, the damage induced in the structure not only depends on the current magnitude reached in the set process, but also on the maximum current reached during the reset phase, with both current levels severely affecting the long-term switching capability of the devices.

A novel AB4-type RE–Mg–Ni–Al-based hydrogen storage alloy with high power for nickel-metal hydride batteries

La–Mg–Ni-based superlattice structure compounds are believed to be a promising negative electrode material with high power and superior hydrogen storage capacity for nickel-metal hydride batteries. They are built with [AB5] and [A2B4] subunits, stacked along the c axis, with the following two sequences: one of rhombohedral and the other of hexagonal symmetry, called 3R and 2H, respectively. In this paper, we present the synthesis conditions and detailed structural characterization of rhombohedral La0.63Nd0.16Mg0.21Ni3.53Al0.11 with the AB4-type structure. It is demonstrated that the AB4 phase is formed by a peritectic reaction between Pr5Co19-type (2H) phase and one liquid phase in a range of 1000–1010 °C. The compound exhibits a high discharge capacity of 391.2 mAh g−1 and can reach 286.2 mAh g−1 even at a discharge current of 1800 mA g−1. The superior high rate dischargeability performance could be attributed to its preferable charge transfer rate and hydrogen diffusion speed. Furthermore, the cycling life of the AB4 compound is up to 83.3% after 200 cycles. As a result of these desirable electrochemical properties, the AB4-type La–Mg–Ni-based compound with high power is considered to promote applications for high power battery materials.

A tetranuclear nickel(II) complex for water oxidation: Meeting new challenges

Ni complexes are promising catalysts for water splitting. Herein, a tetranuclear nickel(II) complex with bis-[(E)-N′-(1-(pyridin-2-yl)ethylidene)]carbohydrazide (HL), was synthesized and characterized by spectroscopic methods and single crystal X-ray analysis. The complex is a tetranuclear complex and the ligands are coordinated to the metal ions in the mono-negative form, (L)- to form a tetranuclear [NiL]44+ unit. Each Ni(II) ion is six-coordinated by pyridine nitrogen, azomethine nitrogen and oxygen atoms of two perpendicular carbohydrazone ligands in the mer configuration. The complex was studied as a water-oxidizing catalyst. In the next step, the role of the Ni-based compound for water oxidation on the surface of fluorine doped tin oxide as one of the true catalysts was investigated by scanning transmission electron microscopy, scanning transmission electron microscopy, spectroelectrochemistry, and electrochemistry. The electrode after water oxidation by the complex was studied and a relation between the decomposition of the Ni complex and water-oxidation reaction was proposed. The experiments show that under water-oxidation condition in the presence of the complex, a Ni-based compound on the electrode is a candidate as a contributor to the observed catalysis.

ChemInform Abstract: Solid‐state Reaction of Nickel Silicide and Germanide Contacts to Semiconductor Nanochannels

The surge in advancing the materials science of solid-state reactions for nanoscale contacts to advanced semiconductor devices necessitates a comprehensive dissemination and discussion on recent progress. The objective of this work is to review the notable developments in compound and alloy contact formation to nanoscale nanowire channels made of germanium, silicon, and their heterostructures, and to develop a unifying framework for understanding the significantly distinct reaction behaviors from those commonly observed in bulk. The Ni-based compound and alloy contacts are used as a platform to highlight the size-relevant, thermodynamic, and kinetic differences, and their key material, reaction, and electronic parameters and properties are summarized. Special attention is given to the interplay between the compound/alloy contact structure and the resultant electronic properties.

Synthesis and Electrochemical Characterization of NaxMO2 as Electrode Materials for Sodium-Ion Batteries

Nowadays, Na-ion batteries have been largely investigated for large scale applications such as grid storage and transportation because of the huge availability of sodium, its low cost and the similarity of both Li and Na insertion chemistries[[i]]. Some efforts have also been devoted to meet requirements in electric and portable devices such as cell phone or laptop. To do this, we must solve problems involving structural collapse due to high volume change during insertion/deinsertion. A good way to design the sodium electrode materials is by starting with analogue ones that function well for Li-ion batteries[i]. Layer structure of NaxMO2 composition seem to be greatly promising[i] due to its high capacity as well as good structural stability. This work presents structure study and electrochemical behaviors of NaxMO2 (M = Mn, Ni and Co) as positive electrode materials synthesized by solid state reaction at 800oC. X-ray diffraction showed that structure of cobalt-based compound was the same as layer P2-Na0.74CoO2 [[ii]]. The single phase of Na0.44MnO2 was obtained by using difference manganese precursors (carbonate, acetate and electrolytic manganese dioxide) and the compound used acetate precursor revealed the best crystallinity. Ni-based compound could not form without O2 oxidation atmosphere. Cyclic voltammetry and charge/discharge testing in Swagelok cell with Na metal as anode between 2 - 3.8 V vs Na+/Na exhibited a series of phase transitions. We also determined the diffusion of sodium ion into tunnel structure by GITT Technique. The results will be further discussed. Acknowledgements This work was supported by National Foundation for Science and Technology Development (Nafosted) through Project Fund granted of 104.03-2012.46. References [i] Simon Engelke, Storage4, 2013, 1, 1.[ii] J.J. Ding, Y.N. Zhou, Q. Sun, X.Q. Yu, X.Q. Yang, Z.W. Fu, Electrochemica Acta, 87, (2013), 488-393.

Solid-state reaction of nickel silicide and germanide contacts to semiconductor nanochannels

The surge in advancing the materials science of solid-state reactions for nanoscale contacts to advanced semiconductor devices necessitates a comprehensive dissemination and discussion on recent progress. The objective of this work is to review the notable developments in compound and alloy contact formation to nanoscale nanowire channels made of germanium, silicon, and their heterostructures, and to develop a unifying framework for understanding the significantly distinct reaction behaviors from those commonly observed in bulk. The Ni-based compound and alloy contacts are used as a platform to highlight the size-relevant, thermodynamic, and kinetic differences, and their key material, reaction, and electronic parameters and properties are summarized. Special attention is given to the interplay between the compound/alloy contact structure and the resultant electronic properties.

Relevance of the catalytic activity on the performance of a NiO/CaAl2O4 oxygen carrier in a CLC process

This paper presents a detailed investigation related to the physical and chemical changes underwent by a low Ni content oxygen carrier during 90h of continuous operation in a CLC plant [1]. The oxygen carrier reached a combustion efficiency of 99% with a metallic Ni inventory of 17kg/MWth, which was the lowest value found in literature for any kind of Ni-based oxygen carrier. The present study was carried out in order to find the reasons by which this material exhibited a different combustion behavior in relation to other Ni-based oxygen carriers. Fresh and after-used particles were characterized by several techniques. XRD, TPR-TPO and XPS techniques proved that the use of CaAl2O4 as oxygen carrier support avoided the formation of NiAl2O4, which is a less reactive Ni-based compound than NiO and always formed in other Ni-based materials. The fact that all the NiO impregnated was found as free NiO in the oxygen carrier particles implied that this material maintained a high reactivity after 90h of continuous CLC operation. The results obtained in the batch fluidized bed reactor have revealed the great relevance of the catalytic activity of the metallic Ni on the global fuel gas combustion process. The low Ni content present in this material makes necessary the use of very high reduction solid conversion to have enough metallic Ni in the fuel reactor to catalyze the CH4 reforming reaction, and therefore to obtain high combustion efficiencies. This result will become very relevant for the design of a CLC unit using this Ni-based material as oxygen carrier.

Formation of Small Hole Polarons in Olivine Phosphate Cathode Materials

We investigate polaron formation in olivine LiMnPO4, LiFePO4, LiCoPO4 and LiNiPO4 using a combination of first principles calculations and experimental XPS spectra. We determine that details of the electronic structure near the Fermi energy, relevant to localization of a hole polaron, are not accurately captured using the standard GGA+U methodology and require a hybrid functional approach. We show that polaron formation is possible in all but the Ni-based compound and discuss the possibility of an electronic instability caused by electron withdrawal during delithiation caused by oxygen evolution.

Study of Plasma Cladding Ni-Based Compound Powder Layers on Q235 Steel

By plasma cladding technology, the Ni60B/TiC composite coating metallurgically bonded to Q235 steel were prepared using Ni-based alloy and TiC powders. The microstructure formation mechanism of the clad layers was investigated by scanning electron microscopy (SEM) and X-ray Diffraction (XRD). The microhardness distribution and wear resistance of the specimens were tested. The results show that metallurgical combination is achieved between coating and substrate, the microstructure of composite coating is composed of dendrite γ-Ni, α-Fe, added TiC and FeNi. The hardness and wear resistance of composite coating have relationship with TiC particles content and TiC particles distribution. The hardness and wear resistance increase with the increase of TiC particles content.

First-principles study of Ni-based metal compound

The rare earth-transition (R-T) intermetallics has excellent physical and chemical properties. The electronic structure, the band structure and the magnetic properties of the compound Ni13Nd3B2 are studied by using the first-principles plane wave pseudopotential method and the local spin-density approximation (LSDA). The calculation results indicate that this system is a metallic conductor with a very small band gap. The system has very complex bonding, where Nd atoms and the neighboring Ni and B atoms form ionic banding, whereas Ni atoms and the neighboring Ni atoms form covalent bonding. Under LSDA approximation, the system has Nd-Ni ferromagnetic coupling, and the total magnetic moment ( 8.4329B) is provided by the local Nd magnetic moment. The Nd-4f, Ni-3p, Nd-5p electron spin splittings due to spin polarization result in the magnetic system.

A Curtin–Hammett mechanism for the copolymerization of ethylene and methyl acrylate monomer using a PymNox nickel catalyst as revealed by DFT computational studies

In this work, the copolymerization of ethylene and methyl acrylate (MA) as catalyzed by a new Ni-based PymNox organometallic compound was studied computationally. We recently tested the behavior of this type of catalyst in ethylene homopolymerization. Experimental results show that the unsubstituted catalyst Ni2 (aldimino PymNox catalyst) is unable to incorporate the MA monomer, whereas methyl-substituted Ni1 (acetaldimino PymNox catalyst) is able to achieve copolymerization. The reactivities of both catalysts were examined using density functional theory (DFT) models. Based on energy profiles calculated at the BP86 level, a Curtin-Hammett mechanism was proposed to explain the different reactivities of the catalysts in ethylene/MA copolymerization. Our results indicate that the methyl substituent Ni1 introduces additional steric hindrance that results in a catalyst conformation that is better suited to polar monomer incorporation. This model provides insights into the design of new catalysts to produce polar functionalized copolymers based on ethylene.

Crystal structure and magnetic properties of the new cobalt tellurite halide Co 5(TeO 3) 4X 2 (X = Cl, Br)

Two new cobalt tellurite halides Co 5(TeO 3) 4Cl 2 and Co 5(TeO 3) 4Br 2 have been synthesized and found to be iso-structural with Ni 5(TeO 3) 4X 2 (X = Cl, Br). Co 5(TeO 3) 4X 2 crystallizes in the monoclinic system space group C2/ c, and the Br-phase has the lattice parameters a = 20.440(1) Å, b = 5.2760(2) Å, c = 16.4710(7) Å, β = 124.790(5)°, and Z = 4. The crystal structures were solved from single-crystal X-ray data, R1 = 1.90 and 1.77, respectively, for the Cl- and Br-phases. The crystal structure is layered with only weak van der Waals' interactions in between the layers. The layers are built by large [Co 5O 16X 2] groups consisting of five edge- and face-sharing Co-octahedra. Each group is connected to adjacent groups via corner sharing through common oxygen atoms as well as through [TeO 3E] groups. Magnetic susceptibility measurements on oriented single crystals reveal pronounced anisotropy in a broad temperature range and clear signs of antiferromagnetic ordering at low temperatures. Anisotropic susceptibility of an iso-structural Ni-based compound was also studied and compared with the corresponding results of Co 5(TeO 3) 4X 2. Magnetic anisotropy is discussed in framework of single-ion anisotropy effects.

Resource Recovery of Inorganic Solid Waste for Reduction of Environmental Load

Resource recovery of inorganic solid waste, such as waste incineration fly ash, cupola dust discharged from foundries, and nickel metal hydride battery waste, have been investigated. From results, tobermorite (Al-substituted tobermorite) and zeolitic compounds (zeolites A and P), which exhibit removal characteristics for toxic cations, were prepared from waste incineration fly ash by hydrothermal treatment in the presence of NaOH solution. Pretreatment of waste incineration fly ash with water washing and heating at 800°C was essential for preparing reproducible tobermorite as a major product at 180°C, while pretreatment with HCl solution, in addition to water washing and heating at 800°C, was essential for preparing reproducible zeolites A and P, as major products at 60-120°C. The H 2 S sorptive property of cupola dust was induced by spinel-type nanocrystals composed of transition elements in the dust at room temperature in existence of water vapor, and drastically enhanced by NaOH treatments at 80-125°C to extract the spinel-type nanocrystals from amorphous SiO 2 matrix. The further examination revealed that the water adsorbed on the surface of the spinel-type nanocrystals played a role as a sorptive field. The Ni-based compound (w-NiO) was prepared from nickel metal hydride battery waste by a series of acid and base treatments. The CH 4 conversion over w-NiO was superior to that over regent NiO (r-NiO) for the CH 4 dry reforming, and exhibited an unusual behavior. The differences of catalytic activities between w-NiO and r-NiO were attributed to carbon deposition by side reactions and sinterability of the resulting Ni from NiO.

Unusual CH 4 dry reforming performance over Ni-based catalyst separated from nickel metal hydride battery waste

The Ni-based compound (s-NiO) has been successfully separated from nickel metal hydride battery waste by a series of acid and base treatments. The catalytic activity of s-NiO reduced to Ni metal was investigated for the CH 4 dry reforming at 780 °C. It was found that the CH 4 conversion over s-NiO was superior to that over regent NiO (r-NiO) and exhibited an unusual behavior. The differences of catalytic activities between s-NiO and r-NiO were examined in terms of carbon deposition and the sinterability of the samples. Carbon deposited by side reactions prevented Ni particles from sintering, and Ni fine particles were highly dispersed on the deposited carbon in the sample obtained from s-NiO.