Facile synthesis and high rate capability of Li<Subscript>4</Subscript>Ti<Subscript>5</Subscript>O<Subscript>12</Subscript>/C composite materials with controllable carbon content

A modified ball-milling-assisted green solid reaction method is provided to prepare Li₄Ti₅O₁₂/C composite materials with controllable carbon content. Thermal analysis was utilized to investigate the reaction process and the temperature for eliminating carbon. The added carbon and the time for eliminating the carbon can affect the particle size and greatly improve the cycling stability and rate performance. Besides, the particle size can reach ~60 nm, the Li₄Ti₅O₁₂ eliminated carbon at 600 °C has ~178% higher discharge capacity than that without added carbon after 500 cycles under the same conditions. As for the Li₄Ti₅O₁₂ with a carbon weight of 10.6%, the second discharge capacity can reach 177.2 and 120.8 mAh g⁻¹ at 1 and 20 C rates, respectively. Its discharge capacity still remains at 118.3 mAh g⁻¹ after 500 cycles under various current rates. The results are comparable to those of the reported Li₄Ti₅O₁₂/PAS composite.     

Effects of surface area on electrochemical performance of Li[Ni<Subscript>0.2</Subscript>Li<Subscript>0.2</Subscript>Mn<Subscript>0.6</Subscript>]O<Subscript>2</Subscript> cathode material

The effect of surface area on the electrochemical properties and thermal stability of Li[Ni_0.2Li_0.2Mn_0.6]O₂ powders was characterized using a charge/discharge cycler and DSC (Differential Scanning Calorimeter). The surface area of the samples was successfully controlled from ~4.0 to ~11.7 m² g⁻¹ by changing the molar ratio of the nitrate/acetate sources and adding an organic solvent such as acetic acid or glucose. The discharge capacity and rate capability was almost linearly increased with increase in surface area of the sample powder. A sample with a large surface area of 9.6–11.7 m² g⁻¹ delivered a high discharge capacity of ~250 mAh g⁻¹ at a 0.2 C rate and maintained 62–63% of its capacity at a 6 C rate versus a 0.2 C rate. According to the DSC analysis, heat generation by thermal reaction between the charged electrode and electrolyte was not critically dependent on the surface area. Instead, it was closely related to the type of organic solvent employed in the fabrication process of the powder.     

Electrochemical properties of microwave-assisted reflux-synthesized Mn<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles in different electrolytes for supercapacitor applications

The nanosized Mn₃O₄ particles were prepared by microwave-assisted reflux synthesis method. The prepared sample was characterized using various techniques such as X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), Raman analysis, and transmission electron microscopy (TEM). Electrochemical properties of Mn₃O₄ nanoparticles were investigated using cyclic voltammogram (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge analysis in different electrolytes such as 1 M KCl, 1 M Na₂SO₄, 1 M NaNO₃, and 6 M KOH electrolytes. XRD pattern reveals the formation of single-phase Mn₃O₄ nanoparticles. The FT-IR and Raman analysis also assert the formation of Mn₃O₄ nanoparticles. The TEM image shows the spherical shape particles with less than 50 nm sizes. Among all the electrolytes, the Mn₃O₄ nanoparticles possess maximum specific capacitance of 94 F g⁻¹ in 6 M KOH electrolyte calculated from CV. The order of capacitance obtained by various electrolytes is 6 M KOH > 1 M KCl > 1 M NaNO₃ > 1 M Na₂SO₄. The EIS and galvanostatic charge–discharge results further substantiate with the CV results. The cycling stability of Mn₃O₄ electrode reveals that the prepared Mn₃O₄ nanoparticles are a suitable electrode material for supercapacitor application.     

Preparation and electrochemical performance of Li-rich layered cathode material,Li[Ni<Subscript>0.2</Subscript>Li<Subscript>0.2</Subscript>Mn<Subscript>0.6</Subscript>]O<Subscript>2</Subscript>, for lithium-ion batteries

The Li-rich layered cathode material, Li[Ni_0.2Li_0.2Mn_0.6]O₂, was synthesized via a “mixed oxalate” method, and its structural and electrochemical properties were compared with the same material synthesized by the sol–gel method. X-ray diffraction (XRD) shows that the synthesized powders have a layered O₃–LiCoO₂-type structure with the R-3m symmetry. X-ray photoelectron spectroscopy (XPS) indicates that in the above material, Ni and Mn exist in the oxidation states of +2 and +4, respectively. The layered material exhibits an excellent electrochemical performance. Its discharge capacity increases gradually from the initial value of 228 mA hg⁻¹ to a stable capacity of over 260 mA hg⁻¹ after the 10th cycle. It delivers a larger capacity of 258 mA hg⁻¹ at the 30th cycle. The dQ/dV curves suggest that the increasing capacity results from the redox-reaction of Mn⁴⁺/Mn³⁺.     

Improved performances of mechanical-activated LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript>/MWNTs cathode for aqueous rechargeable lithium batteries

LiMn₂O₄/multi-walled carbon nanotubes (MWNTs) composite was synthesized by mechanical activation reaction followed by a heat-treatment (500 °C). The LiMn₂O₄ and LiMn₂O₄/MWNTs as cathodes were investigated in 1 M Li₂SO₄ by cyclic voltammetry (CV), galvanostatic charge/discharge (GC), and electrochemical impedance spectroscopy (EIS). The LiMn₂O₄/MWNTs cathode delivered higher discharge capacity (117 mAh g⁻¹) than LiMn₂O₄ (84.6 mAh g⁻¹). Furthermore, the results from EIS showed that LiMn₂O₄/MWNTs had a faster kinetic process for lithium ion intercalation/de-intercalation than LiMn₂O₄. Besides, LiMn₂O₄/MWNTs had better cycling stability and rate capability than LiMn₂O₄, which was confirmed by GC testing. SEM images showed that a three-dimensional network structure was formed during the mechanical activation, giving a decrease of particle size.     

Combustion synthesis of some compounds in the Li<Subscript>2</Subscript>O-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> system

At least four compounds, viz. LiAlO₂, LiAl₅O₈, Li₅AlO₄ and Li₂Al₄O₇, are known in the Li₂O-Al₂O₃ system. These compounds are important for several technological applications. Combustion synthesis of these compounds using urea as a fuel was attempted. LiAlO₂ and LiAl₅O₈ could be successfully prepared by choosing the starting materials in required stoichiometric ratios. Li₂Al₄O₇ was not obtained as a pure phase; γ-LiAlO₂ was formed as an impurity phase. Li₅AlO₄ could not be prepared by combustion process. Some phosphors based on these aluminates could also be prepared. Activation of these aluminates with Fe³⁺, Mn⁴⁺, Cu⁺, etc. was successfully achieved. Excitation and emission spectra for LiAl₅O₈: Fe³⁺, LiAl₅O₈: Mn²⁺, and Li₂Al₄O₇: Cu⁺ are reported.     

Chemical and electrochemical characterization of TiO<Subscript>2</Subscript>/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> atomic layer depositions on AZ-31 magnesium alloy

In this study, innovative TiO₂/Al₂O₃ mono/multilayers were applied by atomic layer depositions (ALD) on ASTM-AZ-31 magnesium/aluminum alloy to enhance its well-known scarce corrosion resistance. Four different configurations of ALD layers were tested: single TiO₂ layer, single Al₂O₃ layer, Al₂O₃/TiO₂ bilayer and Al₂O₃/TiO₂/Al₂O₃/TiO₂ multilayer deposited using Al[(CH₃)]₃ (trimethylaluminum, TMA), and TiCl₄ and H₂O precursors. All depositions were performed at 120°C to obtain an amorphous-like structure of both oxide layers. The four coatings were then investigated using different techniques, such as scanning electron microscope (SEM), stylus profilometer, glow discharge optical emission spectrometry (GDOES) and polarization curves in 0.05-M NaCl solution. The thickness of all the coatings was around 100 nm. The layers compositions were successfully investigated by the GDOES technique, although obtained data seem to be affected by substrate roughness and differences in sputtering rates between ceramic oxides and metallic magnesium alloy. Corrosion resistance showed to be strongly enhanced by the nanometric coatings, giving lower corrosion current densities in 0.05-M NaCl media with respect to the uncoated substrate (from 10⁻⁴ to 10⁻⁶ A/cm² for the single layers and from 10⁻⁴ to 10⁻⁸ A/cm² for the bi- and multilayers). All polarization curves on coated samples also showed a passive region, wider for the bi-layer (from −0.58 to −0.43 V with respect to Ag/AgCl) and multilayer (from −0.53 to −0.38 V with respect to Ag/AgCl) structures.     

Comparative study of the preparation and electrochemical performance of LiNi<Subscript>1</Subscript><Subscript>/2</Subscript>Mn<Subscript>1/2</Subscript>O<Subscript>2</Subscript> electrode material for rechargeable lithium batteries

Positive electrode material LiNi_1/2Mn_1/2O₂ was synthesized via the carbonate co-precipitation method and the hydroxide precipitation route to study the effects of the precursor on its structural and electrochemical properties. The results of X-ray diffraction and Rietveld refinement show that the carbonate precursor of Ni²⁺ and Mn²⁺ exhibits one phase at a pH of 8.5, while the hydroxide deposit separates into Ni(OH)₂ and Mn(OH)₂ phases under the same experimental conditions. LiNi_1/2Mn_1/2O₂ material prepared from the hydroxide precursor shows 8.9% Li/Ni exchange and a large capacity loss of 11.3% in the first 10 cycles. By contrast, more uniform distribution of transition metal ions and stable Mn²⁺ in the carbonate precursor contribute to only 7.8% Li/Ni disorder in the obtained LiNi_1/2Mn_1/2O₂, which delivers a reversible capacity of about 182 mAh g⁻¹ at a current rate of 14 mA g⁻¹ between 2.5 and 4.8 V.     

Synthesis and catalytic properties of nanostructured Me/Mn<Subscript>0.5</Subscript>Ce<Subscript>0.5</Subscript>O<Subscript>2</Subscript> in the oxidation of carbon monoxide

The nanostructured solid solution Mn_0.5Ce_0.5O₂ is synthesized to develop effective noble metal free catalysts for the detoxification of technogenic contaminants. Its chemical and phase compositions and textural characteristics are studied by differential thermal analysis, X-ray diffraction analysis, laser mass spectrometry, and low-temperature nitrogen adsorption. The activity of the solid solution in the oxidation of carbon monoxide is determined by the flow method within a temperature range of 20–300°C at atmospheric pressure, a gas hourly space velocity of 1800 h⁻¹ for the following gas mixture composition, vol %: CO, 3.6; O₂, 8.0; N₂, balance. The activity of Mn_0.5Ce_0.5O₂ is shown to be appreciably higher than the activity of MnO_x and CeO₂, and the temperature of 100% conversion is 92, 120, and 210°C, respectively. Using the solid solution as a support and the technique of impregnation, we synthesize the nanostructured catalysts Cu/Mn_0.5Ce_0.5O₂ and Ag/Mn_0.5Ce_0.5O₂, which manifest high activity in the oxidation of carbon monoxide: the temperature of 100% conversion is 77 and 85°C, respectively. The new catalysts could be of interest for the purification of industrial and motor vehicle wastes.     

Synthesis of Heterogeneous Li<Subscript>4</Subscript>Ti<Subscript>5</Subscript>O<Subscript>12</Subscript> Nanostructured Anodes with Long-Term Cycle Stability

The 0D-1D Lithium titanate (Li₄Ti₅O₁₂) heterogeneous nanostructures were synthesized through the solvothermal reaction using lithium hydroxide monohydrate (Li(OH)·H₂O) and protonated trititanate (H₂Ti₃O₇) nanowires as the templates in an ethanol/water mixed solvent with subsequent heat treatment. A scanning electron microscope (SEM) and a high resolution transmission electron microscope (HRTEM) were used to reveal that the Li₄Ti₅O₁₂ powders had 0D-1D heterogeneous nanostructures with nanoparticles (0D) on the surface of wires (1D). The composition of the mixed solvents and the volume ratio of ethanol modulated the primary particle size of the Li₄Ti₅O₁₂ nanoparticles. The Li₄Ti₅O₁₂ heterogeneous nanostructures exhibited good capacity retention of 125 mAh/g after 500 cycles at 1C and a superior high-rate performance of 114 mAh/g at 20C.     

Determination of cadmium (II) using H<Subscript>2</Subscript>O<Subscript>2</Subscript>-oxidized activated carbon modified electrode

Pristine activated carbon (AcC) was oxidized by H₂O₂ under ultrasonic conditions. Compared with pristine AcC, the H₂O₂-oxidized AC possesses higher accumulation ability to trace levels of Cd²⁺. Based on this, a highly sensitive, simple and rapid electrochemical method was developed for the determination of Cd²⁺. In 0.01 mol L⁻¹ HClO₄ solution, Cd²⁺ was effectively accumulated at the surface of H₂O₂-oxidized AcC modified paste electrode, and then reduced to Cd under −1.10 V. During the following potential sweep from −1.10 to −0.50 V, reduced Cd was oxidized and a sensitive stripping peak appears at −0.77 V. The stripping peak current of Cd²⁺ changes linearly with concentration over the range 5.0 × 10⁻⁸ to 5.0 × 10⁻⁶ mol L⁻¹. The limit of detection was found to be 3.0 × 10⁻⁸ mol L⁻¹ for 2-min accumulation. Finally, this new sensing method was successfully used to detect Cd²⁺ in waste water samples.     

Preparation and properties of Co<Subscript>3</Subscript>O<Subscript>4</Subscript> nanorods as supercapacitor material

Co₃O₄ nanorods have been successfully synthesized by thermal decomposition of the precursor prepared via a facile and efficient microwave-assisted hydrothermal method, using cetyltrimethylammonium bromide (CTAB) with ordered chain structures as soft template for the first time. The obtained Co₃O₄ was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical measurements. The results demonstrate that the as-synthesized nanorods are single crystalline with an average diameter of about 20 to 50 nm and length up to several micrometers. Preliminary electrochemical studies, including cyclic voltammetry (CV), galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS) measurements, are carried out in 6 M KOH electrolyte. Specific capacitance of 456 F g⁻¹ for a single electrode could be achieved even after 500 cycles, suggesting its potential application in electrochemical capacitors. This promising method could provide a universal green chemistry approach to synthesize other low-cost and environmentally friendly transition metal hydroxide or oxide.     

Fe-doping effects on the structural and electrochemical properties of 0.5Li<Subscript>2</Subscript>MnO<Subscript>3</Subscript>·0.5LiMn<Subscript>0.5</Subscript>Ni<Subscript>0.5</Subscript>O<Subscript>2</Subscript> electrode material

With the aim of achieving a high-performance 0.5Li₂MnO₃·0.5LiMn_0.5Ni_0.5O₂ material, a series of 0.5Li₂MnO₃·0.5LiMn _x Ni _y Fe_(1−x−y)O₂ (0.3 ≤ x ≤ 0.5, 0.4 ≤ y ≤ 0.5) samples with low Fe content was synthesized via coprecipitation of carbonates. Its crystal structure and electrochemical performance were characterized by means of powder X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, galvanostatic charge/discharge testing, cyclic voltammetry, and electrochemical impedance spectra. Rietveld refinements with a model integrating R [`3] \overline{3} m and Fm [`3] \overline{3} m indicate that a low concentration of Fe incorporated in 0.5Li₂MnO₃·0.5LiMn_0.5Ni_0.5O₂ decrease a disordered cubic domain of the composite structure. The preferential distribution of Fe in cubic rock-salt contributes to an unimaginable decrease of c-axis parameter of the predominant layered structure as the Fe content increases. Moreover, including Fe as a dopant can kinetically improve crystallization and also change the ratio of Mn³⁺/Mn⁴⁺ and Ni³⁺/Ni²⁺. As a result, 0.5Li₂MnO₃·0.5LiMn_0.4Ni_0.5Fe_0.1O₂ exhibits lower Warburg impedance and higher reversible capacity than the undoped material.     

Photoelectrochemical characterization of the synthetic crednerite CuMnO<Subscript>2</Subscript>

High quality crednerite CuMnO₂ was prepared by solid state reaction at 950 °C under argon flow. The oxide crystallizes in a monoclinically distorted delafossite structure associated to the static Jahn–Teller (J–T) effect of Mn³⁺ ion. Thermal analysis showed that it converts reversibly to spinel Cu _x Mn_3−x O₄ at ~420 °C in air and further heating reform the crednerite above 940 °C. CuMnO₂ is p-type, narrow semiconductor band gap with a direct optical gap of 1.31 eV. It exhibits a long-term chemical stability in basic medium (KOH 0.5 M), the semi logarithmic plot gave an exchange current density of 0.2 μA cm⁻² and a corrosion potential of ~−0.1 V_SCE. The electrochemical oxygen insertion/desinsertion is evidenced from the intensity–potential characteristics. The flat band potential (V _fb = −0.26 V_SCE) and the holes density (N _A  = 5.12 × 10¹⁸ cm⁻³) were determined, respectively, by extrapolating the curve C ⁻² versus the potential to the intersection with C ⁻²  = 0 and from the slope of the Mott–Schottky plot. From photoelectrochemical measurements, the valence band formed from Cu-3d wave function is positioned at 5.24 ± 0.02 eV below vacuum. The Nyquist representation shows straight line in the high frequency range with an angle of 65° ascribed to Warburg impedance originating from oxygen intercalation and compatible with a system under mass transfer control. The electrochemical junction is modeled by an equivalent electrical circuit thanks to the Randles model.     

Facile synthesis of nano-Li<Subscript>4</Subscript> Ti<Subscript>5</Subscript>O<Subscript>12</Subscript> for high-rate Li-ion battery anodes

One of the most promising anode materials for Li-ion batteries, Li₄Ti₅O₁₂, has attracted attention because it is a zero-strain Li insertion host having a stable insertion potential. In this study, we suggest two different synthetic processes to prepare Li₄Ti₅O₁₂ using anatase TiO₂ nanoprecursors. TiO₂ powders, which have extraordinarily large surface areas of more than 250 m² g^-1, were initially prepared through the urea-forced hydrolysis/precipitation route below 100°C. For the synthesis of Li₄Ti₅O₁₂, LiOH and Li₂CO₃ were added to TiO₂ solutions prepared in water and ethanol media, respectively. The powders were subsequently dried and calcined at various temperatures. The phase and morphological transitions from TiO₂ to Li₄Ti₅O₁₂ were characterized using X-ray powder diffraction and transmission electron microscopy. The electrochemical performance of nanosized Li₄Ti₅O₁₂ was evaluated in detail by cyclic voltammetry and galvanostatic cycling. Furthermore, the high-rate performance and long-term cycle stability of Li₄Ti₅O₁₂ anodes for use in Li-ion batteries were discussed.     

Initiation of combustion of a CH<Subscript>4</Subscript>-O<Subscript>2</Subscript> mixture in a supersonic flow with excitation of O<Subscript>2</Subscript> molecules by an electric discharge

The possibility of intensification of ignition of a methane-oxygen mixture in a supersonic flow behind the front of an oblique shock wave by means of excitation of O₂ molecules to the states a ¹Δ_g and b ¹Σ_g⁺ in an electric discharge is discussed. Through numerical simulations, activation of O₂ molecules by an electric discharge is demonstrated to speed up chain reactions in the CH₄-O₂ mixture and to reduce the induction-zone length. Even a small amount of energy input to O₂ molecules in the discharge (≈3·0⁻² J/cm³) can reduce the ignition-delay length by a factor of hundreds and initiate combustion at distances of ≈1 m from the discharge zone at comparatively low temperatures of the gas behind the front (≈1000 K) and moderate pressures (≈10⁵ Pa). Excitation of O₂ molecules by an electric discharge is much more efficient than simple heating of the mixture. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 3, pp. 3–16, May–June, 2008.     

Photoelectrochemical reaction of biomass-related compounds in a biophotochemical cell comprising a nanoporous TiO<Subscript>2</Subscript> film photoanode and an O<Subscript>2</Subscript>-reducing cathode

Photoelectrochemical decomposition of bio-related compounds such as ammonia, formic acid, urea, alcohol, and glycine by a biophotochemical cell (BPCC) comprising a nanoporous TiO₂ film photoanode and an O₂-reducing cathode generating simultaneously electrical power was investigated. The bio-related compounds studied were all photodecomposed by the present BPCC when they were either liquid or soluble in water. It was shown that ethanol exhibits similar characteristics both under 1 atm O₂ and air as studied by cyclic voltammograms. Although the present BPCC utilizes only UV light, a solar simulator at AM 1.5G and 100 mW cm⁻² light intensity gave also moderate photocurrent–photovoltage (J–V) characteristics with about 2/5 of the short circuit photocurrent (J _sc) values (J _sc) of that under a Xe lamp irradiation at the intensity of 503 mW cm⁻². It was demonstrated that varieties of bio-related compounds can be used as a direct fuel simultaneously for photodecomposition and electrical power generation. The charge transport processes in the BPCC operation were analyzed using glycine by an alternating current impedance spectroscopy, showing that the charge transfer reactions on the photoanode and the cathode surfaces compose the major resistance for the cell performance.     

High-rate, high capacity ZrO2 coated Li[Li1/6Mn1/2Co1/6Ni1/6]O2 for lithium secondary batteries

Recently, there have been many reports on efforts to improve the rate capability and discharge capacity of lithium secondary batteries in order to facilitate their use for hybrid electric vehicles and electric power tools. In the present work, we present a ZrO₂-coated Li[Li_1/6Mn_1/2Co_1/6Ni_1/6]O₂. The bare Li[Li_1/6Mn_1/2Co_1/6Ni_1/6]O₂ shows a high initial discharge capacity of 224 mAh g⁻¹ at a 0.2 C rate. Owing to the stability of ZrO₂, it was possible to enhance the rate capability and cyclability. After 1 wt% ZrO₂ coating, the ZrO₂-coated Li[Li_1/6Mn_1/2Co_1/6Ni_1/6]O₂ showed a high discharge capacity of 115 mAh g⁻¹ after 50 cycles under a 6 C rate, whereas the bare Li[Li_1/6Mn_1/2Co_1/6Ni_1/6]O₂ showed a discharge capacity of only 40 mAh g⁻¹ and very poor cyclability under the same conditions. Based on results of XRD and EIS measurements, it was found that the ZrO₂ suppressed impedance growth at the interface between the electrodes and electrolyte and prevented collapse of the layered hexagonal structure.     

LiNi<Subscript>0.4</Subscript>Co<Subscript>0.3</Subscript>Mn<Subscript>0.3</Subscript>O<Subscript>2</Subscript> thin film electrode by aerosol deposition

LiNi_0.4Co_0.3Mn_0.3O₂ thin film electrodes are fabricated from LiNi_0.4Co_0.3Mn_0.3O₂ raw powder at room temperature without pretreatments using aerosol deposition that is much faster and easier than conventional methods such as vaporization, pulsed laser deposition, and sputtering. The LiNi_0.4Co_0.3Mn_0.3O₂ thin film is composed of fine grains maintaining the crystal structure of the LiNi_0.4Co_0.3Mn_0.3O₂ raw powder. In the cyclic voltammogram, the LiNi_0.4Co_0.3Mn_0.3O₂ thin film electrode shows a 3.9-V anodic peak and a 3.6-V cathodic peak. The initial discharge capacity is 44.6 μAh/cm², and reversible behavior is observed in charge-discharge profiles. Based on the results, the aerosol deposition method is believed to be a potential candidate for the fabrication of thin film electrodes.     

Facile Solvothermal Synthesis Ni(OH)<Subscript>2</Subscript> Nanostructure for Electrochemical Capacitors

Nickel hydroxide nanosheets were successfully synthesized by facile solvothermal method without any template. The structure and morphology of the as-prepared sample were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. The observations revealed the formation of hexagonal phase β-Ni(OH)₂ nanosheets with an average diameter of about 100–120 nm. Electrochemical studies were carried out using cyclic voltammetry and galvanostatic charge–discharge tests, respectively. A maximum specific capacitance of 2,342 F g⁻¹, which is the highest reported for a β-Ni(OH)₂ electrode, could be achieved in 6 mol L⁻¹ KOH electrolyte within the potential range of 0–0.50 V (vs. SCE) for the obtained β-Ni(OH)₂ electrode at 0.4 A g⁻¹, suggesting its potential application in the electrode material for electrochemical capacitors.