• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.5
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• pp.268-273
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• 2017

In this study, nickel hydroxide crystalline powders were synthesized by continuous reaction in the taylor fluid flow using nickel chloride, nickel sulphate and sodium hydroxide as raw materials and compared with those prepared by a conventional batch type reaction. The crystallinity of nickel hydroxide prepared by the Taylor fluid flow reaction was higher than that of nickel hydroxide obtained by batch reaction. The particle size of nickel hydroxide decreased about 2.5 to 3.6 times, and the specific surface area was increased.

• Journal of Surface Science and Engineering
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• v.29 no.6
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• pp.724-727
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• 1996

Electrolytic impregnation of nickel hydroxide into porous sintered nickel plaque from various nickel solutions were carried out at room or high temperatures and current density range of 2.5mA $cm^{-2}$ to 25mA $cm^{-2}$. The morphology of the deposited surface was observed with an electron microscope and the surface products were analyzed by means of X-ray diffraction method. Nickel hydroxide was deposited in nickel nitrate electrolyte, while deposits from sulphate or chloride solutions were almost metallic nickel. The loading level of nickel hydroxide from nitrate solutions was 1.6g$cm^{-3}$ void volume and the appearance of the surface was good quality. Discharge capacity of prepared electrodes in nickel nitrate electrolyte was larger than that of the others bath. It was considered that the cell capacity was dependent on the surface roughness of active material.

• Journal of Magnetics
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• v.20 no.3
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• pp.241-245
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• 2015

A study on the preparation of nickel oxide nanoparticles using electron beam irradiation is described. Nickel nanoparticles were synthesized with nickel chloride hexahydrate as a metal precursor and different sodium hydroxide concentrations using electron beam irradiation. The effects of sodium hydroxide concentration and electron beam absorbed doses were investigated. The samples were synthesized at different sodium hydroxide concentrations and with absorbed doses of 100 to 500 kGy at room temperature. Synthesized nanoparticles were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) and a vibrating sample magnetometer (VSM). The nanoparticle morphologies seemed to be non-spherical and aggregated. The 1:1 molar ratio of nickel chloride hexahydrate and sodium hydroxide showed a higher purity and saturation magnetization value of 13.0 emu/g. The electron beam absorbed dose was increased with increasing nickel nanoparticle nucleation.

• Journal of the Korean Electrochemical Society
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• v.11 no.2
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• pp.115-119
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• 2008

Single particle of nickel hydroxide and the surface-treated one with cobalt element were performed to review the effect of LiOH additive in alkaline electrolyte for Ni-MH batteries using microelectrode test system. As a result of cyclic voltammetry, the electrochemical behaviors such as the oxidation/reduction and oxygen evolution reaction are clearly observed for a single particle of nickel hydroxide, respectively. Furthermore, the reduction current peak of nickel hydroxide added with LiOH in electrolyte was very low and broad compared with the normal nickel hydroxide without an additive LiOH, which had a bad effect to the crystallization structure of nickel hydroxide. However, it was found that capacity and cycle properties of the nickel hydroxide treated with cobalt greatly increased by the addition of LiOH.

• Journal of Surface Science and Engineering
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• v.28 no.2
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• pp.92-100
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• 1995

To increase the capacity of positive electrode materials for matching the high capacity negative electrode materials in alkaline rechargeable batteries, high-density nickel hydroxide powders were made through a continuous process from nickel sulfate reacted with ammonia and sodium hydroxidc. The effect of operating conditions on structure, shape, size distribution, apparent density and tap density of powders were investigated. Crystal structure of nickel hydroxide powder was hcp according to Bravais Lattice. The increase of mean residence time promoted the growth of (101) plane. The shape of powder was nearly spherical. Their size was in the range of $2~50\mu\textrm{m}$. The size distribution of the powders prepared was narrower than that of commercially obtained nickel hydroxide. Apparent density and tap density were 1.6~1.7g/cc and 2.0~2.1g/cc, respectively.

• Journal of Surface Science and Engineering
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• v.56 no.5
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• pp.320-327
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• 2023

In this study, the nickel hydroxide (Ni(OH)₂) electrode for supercapacitor was prepared via hydrothermal method. Based on the nickel (Ni) foam, the electrode does not require any additional binder material or post-processing. Nickel nitrate (Ni(NO₃)₂) and hexamethylenetetramine (C₆H₁₂N₄) were used for synthesis, and the synthesis condition was 12 hours at 80 ℃. X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM) were used to analyze the structural characteristics of the electrode, and it shown that the nickel hydroxide was successfully prepared after only the one-step hydrothermal synthesis. The electrochemical properties were analyzed through the half-cell test. The prepared electrode shown a pair of oxidation/reduction peaks, indicating that the driving method included the redox reaction on the electrode surface. After the charge/discharge test, the specific capacitance was calculated as the value of 438 F/g at 3 A/g.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.163-167
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• 2002

Improved optical switching property of electrochromic nickel hydroxide/nickel glass thin film is reported. Nickel metal film was deposited on glass by e-beam evaporation before following electrochemical redox cycling to form nickel hydroxide for electrochromic activation. Without ITO (indium tin oxide) layer as electrical conductor, this electrode showed more rapid coloration rate than nickel hydroxide film on ITO substrate in the change of the electric voltage and optical transmittance. XPS analysis confirmed the existence of ultra-thin nickel metal layer (${\sim}10{\AA}$) between electrochemically grown nickel hydroxide and the glass substrate. It is concluded that the remained nickel metal nano-layer attribute to the conduction layer and the enhanced response time.

• Resources Recycling
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• v.21 no.2
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• pp.41-46
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• 2012

An investigation on the recovery of nickel from spent electroless plating solutions has been performed using the electrowinning method. For this aim, nickel in spent electroless plating solutions was separated as nickel hydroxide through the addition of caustic soda. Nickel hydroxide was completely dissolved with sulfuric acid and an electrolysis was performed for electrowinning of nickel from nickel solutions. As a result, it was found that more than 99% of nickel in spent electroless plating solutions could be precipitated as nickel hydroxide above pH 10 with the addition of caustic soda. As far as the current efficiency in electrowinning of nickel was concerned, it was decreased with increase in the current density.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.292-295
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• 2001

A Study on the precipitation characteristics of nickel hydroxide as well as carbonate and sulfide is carried out to determine the proper treatment condition of the wastewater induced from nickel-plating industry. The nickel concentrations in the effluent could be kept lower than 5ppm when the value of pH was maintained higher than 10. The precipitation of nickel salts by alkaline addition to the nickel containing model wastewater was conducted by using proper amount of sodium hydroxide, sodium carbonate, sodium bicarbonate and sodium sulfide. In case of the sulfide treatment, the residual nickel concentration in the clear water after precipitates removed showed the lowest value. The influences of the precipitation condition upon the particle size of the crystals precipitated were also investigated. In spite of the various precipitation conditions were adopted, the particle size of the precipitated crystals showed no great differences. The sedimentation rates of the precipitated particle bed were observed and the free sedimentation period was terminated within 20 minutes. Although the hindered sedimentation as well as bed compaction progressed subsequently, the bed heights were maintained almost the same level after two hours of sedimentation.

• Journal of Surface Science and Engineering
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• v.54 no.3
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• pp.152-157
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• 2021

The pseudocapacitor has a high energy density characteristic because it accumulates charges through a paradic redox reaction. However, due to its strong insulation properties, metal hydroxides should be designed as structural systems optimized for charge transfer to support fast electron transport. Also, Nickel material is weak to heat and is easily deformed when used as a cathode material, so stability must be secured. In this study, nickel hydroxide was produced by electrodeposition to secure the stability of nickel. Electrodeposition is a synthetic method suitable for growing optimized nickel hydroxide because it allows fine control. Nickel hydroxide (Ni(OH)₂) is a metal hydroxide used as a pseudocapacitor anode due to its high capacitance, electrical conductivity and resistance. Therefore, in order to determine how Ni(OH)₂ nanosheets are formed and what are the optimization conditions, various measurement methods were used to focus on structural growth of nanosheets produced by electrodeposition.