Structure and physical properties of modified β-Ni(OH)2/C composites

Budzulyak

Kotsyubynsky

et al. 2021

The aim of this paper is to establish the optimal content of carbon material in composites with nanocrystal hydrate nickel molybdate. To achieve this, NiMoO4 / C composites with a carbon material content of 1, 5 and 10% by weight (with and without ultrasonic irradiation) were obtained by hydrothermal method. As a result of electrochemical studies, it was found that the maximum specific capacitance of 628 F/g is reached by a composite with a carbon content of 1% after ultrasonic exposure, while this composite shows excellent electrical conductivity, which is 0.47 Ohm-1m-1.

Section: Resultsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Electrochemical and electrical properties of nickel molybdate / carbon material composites

Budzulyak

Kotsyubynsky

et al. 2021

“…However, traditional technologies for obtaining nanomaterials with predetermined structural properties require high temperatures and are energy-intensive. An alternative is laser irradiation of synthesized materials, which is characterized by a much faster and localized thermal effect, allowing for accurate control of the physicochemical properties of the material and its transformation into a more stable energy state [8,9]. A perspective battery-type material for HSC is the nickel molybdate (NiMoO4), which stores charge due to the redox reaction of Ni ions and has high electrical conductivity due to Mo ions [10,11].…”

Section: Introductionmentioning

confidence: 99%

Laser-modified nanocrystalline NiMoO4 as an electrode material in hybrid supercapacitors

Budzulyak²,

Khemii³

et al. 2023

The nanocrystalline NiMoO4 obtained as a result of hydrothermal synthesis was exposed to laser radiation with a pulse energy of 70 mJ/cm2 for 5 minutes. The phase composition and size of crystallites of the triclinic structure of NiMoO4 were determined by X-ray analysis. The average crystallite size was 18 nm for laser-irradiated nickel molybdate. Impedance analysis was used to analyze the temperature dependence of the electrical conductivity of laser-modified NiMoO4. The frequency index of the power law, determined by the nonlinear approximation method, was 0.5-0.67, which corresponds to the hopping mechanism of charge carriers. The electrochemical behavior of NiMoO4 was studied using cyclic voltammetry and galvanostatic charge/discharge testing. The laser-irradiated NiMoO4 reaches a specific capacitance of 553 F/g at a scan rate of 1 mV/s. The hybrid electrochemical system based on electrodes of modified NiMoO4 and carbon material provides high Coulombic efficiency (95%) for a significant number of charge/discharge cycles.

“…Ultrasonic dispersion is an effective method of modifying nanosized materials without the use of high temperatures, pressures and long reaction times [5,6]. The speed of sound in the liquid varies from 1000 to 1500 m/s, and the lengths of ultrasonic waves are from 10 cm to 100 mm with frequencies from 20 kHz to 15 MHz [7].…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic modification of nanocrystalline NiMoO4 hydrate obtained by hydrothermal method

Budzulyak

Kotsyubynsky

et al. 2022

Self Cite

The paper presents the results of studies of the crystal structure, surface morphology and electrical properties of nickel molybdate obtained by hydrothermal method and modified by ultrasound. The influence of the duration of ultrasonic dispersion on the crystallites size, specific surface area, pore size distribution and activation energy of charge carriers of nickel molybdate hydrate is determined. It was found that ultrasound with a frequency of 22 kHz and a duration of 90 min leads to an increase in the total volume of mesopores from 0.135 cm2/g to 0.223 cm2/g with an average diameter of 28.5 nm.