scholarly journals Synthesis and Electrochemical Properties of Nanocrystalline Nickel Molybdate

2021 ◽  
Vol 22 (1) ◽  
pp. 123-131
Author(s):  
O.M. Popovych ◽  
I.M. Budzulyak ◽  
O.V. Popovych ◽  
B.I. Rachiy ◽  
R.V. Ilnytskyi ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Alpha Phase ◽  
Specific Power ◽  
Electrochemical Studies ◽  
Hybrid Supercapacitor ◽  
Hydrothermal Technique ◽  
Nickel Molybdate ◽  
Hybrid Supercapacitors ◽  
Scan Rate ◽  
Cyclic Voltammetry Data

We have obtained nanocrystalline hydrate and alpha phase of nickel molybdate by a hydrothermal technique. On the basis of the obtained cyclic voltammetry data, we have evaluated the contribution of faradaic and non-faradaic processes to the total capacitance of molybdates under study. It was found that the specific capacitance of hydrate NiMoO4·H2O is 621 F/g at a scan rate of 1 mV / s and the specific capacitance of the α-NiMoO4 is 281 F/g. Cathodes for hybrid supercapacitors were formed on the basis of the obtained nickel molybdates. As a result of electrochemical studies, it was found that the specific capacitance of hybrid supercapacitor based on NiMoO4·H2O/C was 256 F/g at the current of 0.2 A/g, while the specific energy was 80 W h/kg and specific power – 304 W/kg and these results are higher below in the α-NiMoO4 /C-based hybrid supercapacitor.

scholarly journals Electrochemical and electrical properties of nickel molybdate / carbon material composites

2021 ◽  
Vol 22 (3) ◽  
pp. 481-486
Author(s):  
O.M. Popovych ◽  
I.M. Budzulyak ◽  
V.O. Kotsyubynsky ◽  
L.S. Yablon ◽  
O.V. Popovych
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Carbon Content ◽  
Specific Capacitance ◽  
Hydrothermal Method ◽  
Ultrasonic Irradiation ◽  
Carbon Material ◽  
Electrochemical Studies ◽  
Nickel Molybdate ◽  
Maximum Specific Capacitance

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.

scholarly journals α- and β-Phase Ni-Mg Hydroxide for High Performance Hybrid Supercapacitors

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1686 ◽  
Author(s):  
Jingzhou Yin ◽  
Guolang Zhou ◽  
Xiaoliang Gao ◽  
Jiaqi Chen ◽  
Lili Zhang ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Magnesium Hydroxide ◽  
High Performance ◽  
High Specific Capacitance ◽  
Electrochemical Performances ◽  
Nickel Salt ◽  
Hybrid Supercapacitor ◽  
Hybrid Supercapacitors ◽  
Β Phase ◽  
High Storage

Mg-substituted α- and β-phase nickel hydroxides with high specific capacitance and good stability have been synthesized via sacrificial metal-based replacement reaction. 2D α- and β-phase nickel-magnesium hydroxide (NiMg-OH) have been synthesized by sacrificing magnesium (Mg) powder with nickel salt aqueous solutions. Interestingly, the phase of the obtained NiMg-OH can be controlled by adjusting the nickel precursor. As well, the Mg powder is used not only as Mg source but also alkali source to form NiMg-OH. The α-phase nickel-magnesium hydroxide sample (α-NiMg-OH) exhibits lager surface area of 290.88 m2 g–1. The electrochemical performances show that the α-NiMg-OH presented a superior specific capacitance of 2602 F g–1 (1 A g–1) and β-phase nickel-magnesium hydroxide sample (β-NiMg-OH) exhibits better stability with 87% retention after 1000 cycles at 10 A g–1. The hybrid supercapacitor composed of α-NiMg-OH and activated carbon (AC) display high storage performance and cycle stability, it presents 89.7 F g–1 (1 A g–1) and of 0–1.6 V potential window and it maintains capacitance retention of 84.6% subsequent to 4000 cycles.

C@KCu7S4 microstructure for solid-state supercapacitors

RSC Advances ◽  
2014 ◽  
Vol 4 (76) ◽  
pp. 40542-40545 ◽  
Author(s):  
Shuge Dai ◽  
Yi Xi ◽  
Chenguo Hu ◽  
Baoshan Hu ◽  
Xule Yue ◽  
...  
Keyword(s):  
Solid State ◽  
Energy Density ◽  
Specific Capacitance ◽  
Light Emitting Diode ◽  
Maximum Power Density ◽  
Capacity Retention ◽  
Light Emitting ◽  
Hybrid Supercapacitors ◽  
Scan Rate ◽  
In Series

Three C/KCu7S4 hybrid supercapacitors units in series can light one light-emitting diode for 3.5 min; the hybrid supercapacitors can deliver the largest specific capacitance of 352 F g−1 at the scan rate of 10 mV s−1, the maximum power density of 994.8 kW kg−1, the highest energy density of 26.2 W h kg−1 and cycling stability (86% capacity retention after 2000 cycles).

scholarly journals Ultrafine beta-FeOOH and Fe3O4 obtained by precipitation method: comparative study of electrical and electrochemical properties

2020 ◽  
Vol 21 (4) ◽  
pp. 680-688
Author(s):  
L.V. Mokhnatska ◽  
V.O. Kotsyubynsky ◽  
V.M. Boichuk ◽  
M.L. Mokhnatskyi ◽  
Kh.V. Bandura ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Specific Capacitance ◽  
Specific Energy ◽  
Electrode Material ◽  
Precipitation Method ◽  
Specific Electrical Conductivity ◽  
Specific Power ◽  
Ultrafine Powders ◽  
Scan Rate ◽  
Frequency Dependences

In this work, ultrafine powders of b-FeOOH and Fe3O4 have been obtained by the precipitation method. The values of the specific surface area for materials b-FeOOH and Fe3O4 are 101 and 135 m2/h. Frequency dependences of specific electrical conductivity have been obtained in the temperature range of 20-150 oC. It has been found that the materials show a superlinear dependence (SPL). In addition, the crossover energies from dc to JPL and from JPL to SPL have been calculated: Edc = 0.55eV, Ep1 = 0.51eB, Ep2 = 0.16eB and Edc = 0.22 eV, Ep1 = 0.21eB, Ep2 = 0.1 eB. Potentiodynamic studies have been performed at a scan rate from 1 mV/s to 50 mV/s. The b-FeOOH electrode material showed a specific capacitance value of 80 F/g at a scan rate of 1 mV/s, while the specific capacitance of the Fe3O4 material reached 32 F/g. Galvanostatic measurements have been done for discharge currents of 0.05 A/g, 0.1 A/g -  0.25 A/g. b-FeOOH sample is characterized by the maximum specific energy value of 8 W h/kg at the value of specific power equal to 20 W/kg, and Fe3O4 material is characterized by the maximum specific energy of about 3.5 W h/kg. 

Potassium Pre-Inserted K1.04Mn8O16 Cathode Materials for Aqueous Li-Ion and Na-Ion Hybrid Capacitors

2019 ◽  
Author(s):  
Yamin Zhang ◽  
Lina Chen ◽  
Chongyang Hao ◽  
Xiaowen Zheng ◽  
Yixuan Guo ◽  
...  
Keyword(s):  
Cycling Performance ◽  
High Energy ◽  
High Energy Density ◽  
Potassium Ions ◽  
Tunnel Structure ◽  
Hybrid Supercapacitor ◽  
Hybrid Supercapacitors ◽  
Li Ion ◽  
Power Densities ◽  
Hybrid Capacitors

For the applications of aqueous Li-ion hybrid capacitors and Na-ion hybrid capacitors, potassium ions are pre-inserted into MnO<sub>2</sub> tunnel structure, the as-prepared K<sub>1.04</sub>Mn<sub>8</sub>O<sub>16</sub> materials consist of <a>nanoparticles</a> and nanorods were prepared by facile high-temperature solid-state reaction. <a></a>The as-prepared materials were well studied andthey show outstanding electrochemical behavior. We assembled hybrid supercapacitors with commercial activated carbon (YEC-8A) as anode and K<sub>1.04</sub>Mn<sub>8</sub>O<sub>16 </sub>as cathode. It has high energy densities and power densities. Li-ion capacitors reach a high energy density of 127.61 Wh kg<sup>-1 </sup>at the power density of 99.86 W kg<sup>-1</sup> and Na-ion capacitor obtains 170.96 Wh kg<sup>-1 </sup>at 133.79 W kg<sup>-1</sup>. In addition, the <a>hybrid supercapacitor</a>s demonstrate excellent cycling performance which maintain 97 % capacitance retention for Li-ion capacitor and 85 % for Na-ion capacitor after 10,000 cycles.

Poly(aniline-co-pyrrole)-coated Ni-doped manganese dioxide as electrode materials for supercapacitors

2020 ◽  
Vol 13 (02) ◽  
pp. 2051007
Author(s):  
Jie Dong ◽  
Qinghao Yang ◽  
Qiuli Zhao ◽  
Zhenzhong Hou ◽  
Yue Zhou ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Manganese Dioxide ◽  
Specific Capacitance ◽  
Electrode Materials ◽  
High Specific Capacitance ◽  
Cycle Stability ◽  
Mass Ratio ◽  
Scan Rate ◽  
Poly Aniline ◽  
Inorganic And Organic

Electrode materials with a high specific capacitance, outstanding reversibility and excellent cycle stability are constantly pursued for supercapacitors. In this paper, we present an approach to improve the electrochemical performance by combining the advantages of both inorganic and organic. Ni-MnO2/PANi-co-PPy composites are synthesized, with the copolymer of aniline/pyrrole being coated on the surface of Ni-doped manganese dioxide nanospheres. The inorganic–organic composite enables a substantial increase in its specific capacitance and cycle stability. When the mass ratio of Ni-MnO2 to aniline and pyrrole mixed monomer is 1:5, the composite delivers high specific capacitance of 445.49[Formula: see text]F/g at a scan rate of 2[Formula: see text]mV/s and excellent cycle stability of 61.65% retention after 5000 cycles. The results indicate that the Ni-MnO2/PANi-co-PPy composites are promising electrode materials for future supercapacitors application.

Heterostructures of Ni–Co–Al layered double hydroxide assembled on V4C3MXene for high-energy hybrid supercapacitors

2019 ◽  
Vol 7 (5) ◽  
pp. 2291-2300 ◽  
Author(s):  
Xin Wang ◽  
Hui Li ◽  
Han Li ◽  
Shuai Lin ◽  
Jin Bai ◽  
...  
Keyword(s):  
Layered Double Hydroxide ◽  
High Energy ◽  
Hybrid Supercapacitor ◽  
Synthetic Process ◽  
Hybrid Supercapacitors ◽  
Double Hydroxide

The synthetic process of the NiCoAl-LDH/V4C3Txcomposite and the assembled NiCoAl-LDH/V4C3Tx//AC hybrid supercapacitor device.

scholarly journals Electrochemical studies on Ni, Co & Ni/Co-MOFs for high-performance hybrid supercapacitors

2020 ◽  
Vol 7 (5) ◽  
pp. 054003 ◽  
Author(s):  
M G Radhika ◽  
B Gopalakrishna ◽  
K Chaitra ◽  
Lakshminarayana Kudinalli Gopalakri Bhatta ◽  
Krishna Venkatesh ◽  
...  
Keyword(s):  
High Performance ◽  
Electrochemical Studies ◽  
Hybrid Supercapacitors

scholarly journals Preparation of Flower-like Nickel-Based Bimetallic Organic Framework Electrodes for High-Efficiency Hybrid Supercapacitors

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1425
Author(s):  
Di Jiang ◽  
Chuanying Wei ◽  
Ziyang Zhu ◽  
Xiaohui Xu ◽  
Min Lu ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Electrode Materials ◽  
High Efficiency ◽  
Specific Capacity ◽  
Maximum Energy ◽  
Cycle Life ◽  
High Porosity ◽  
Hybrid Supercapacitors ◽  
Metal Organic ◽  
General Method

Metal organic frameworks (MOFs) have been rapidly developed in the application of electrode materials due to their controllable morphology and ultra-high porosity. In this research, flower-like layered nickel-based bimetallic MOFs microspheres with different metal central ions were synthesized by solvothermal method. Compared with Ni-MOFs, the optimization of the specific capacitance of NiCo-MOFs and NiMn-MOFs was been confirmed. For example, the specific capacitance of NiCo-MOFs can reach 882 F·g−1 at 0.5 A·g−1 while maintaining satisfactory cycle life (the specific capacity remains 90.1% of the initial value after 3000 charge-discharge cycles at 5 A·g−1). In addition, the NiCo-MOFs//AC HSCs, which are composed of NiCo-MOFs and activated carbon (AC), achieved a maximum energy density of 18.33 Wh·kg−1 at a power density of 400 W·kg−1, and showed satisfactory cycle life (82.4% after 3000 cycles). These outstanding electrochemical properties can be ascribed to the synergistic effect between metal ions, the optimized conductivity, and the unique layered stacked flower structure, which provides a smooth transmission channel for electrons/ions. In addition, this research gives a general method for the application of MOFs in the field of supercapacitors.

scholarly journals Time-Domain Circuit Modelling for Hybrid Supercapacitors

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6837
Author(s):  
Fabio Corti ◽  
Michelangelo-Santo Gulino ◽  
Maurizio Laschi ◽  
Gabriele Maria Lozito ◽  
Luca Pugi ◽  
...  
Keyword(s):  
Time Domain ◽  
Black Box ◽  
Circuit Modeling ◽  
Hybrid Supercapacitor ◽  
Hybrid Supercapacitors ◽  
Linear Behavior ◽  
Modeling Techniques ◽  
The Time Domain ◽  
Short Time ◽  
Circuit Modelling

Classic circuit modeling for supercapacitors is limited in representing the strongly non-linear behavior of the hybrid supercapacitor technology. In this work, two novel modeling techniques suitable to represent the time-domain electrical behavior of a hybrid supercapacitor are presented. The first technique enhances a well-affirmed circuit model by introducing specific non-linearities. The second technique models the device through a black-box approach with a neural network. Both the modeling techniques are validated experimentally using a workbench to acquire data from a real hybrid supercapacitor. The proposed models, suitable for different supercapacitor technologies, achieve higher accuracy and generalization capabilities compared to those already presented in the literature. Both modeling techniques allow for an accurate representation of both short-time domain and steady-state simulations, providing a valuable asset in electrical designs featuring supercapacitors.

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