Effect of dopant on the morphology and electrochemical performance of Ni1-xCaxCo2O4 (0 ≤ x ≤ 0.8) oxide hierarchical structures

MRS Advances ◽  
2020 ◽  
pp. 1-8
Author(s):  
D. Guragain ◽  
C. Zequine ◽  
R. Bhattarai ◽  
J. Choi ◽  
R. K. Gupta ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Energy Band ◽  
Electrode Materials ◽  
Morphological Structure ◽  
Hierarchical Structures ◽  
High Specific Capacitance ◽  
Supercapacitor Electrode ◽  
Binary Metal Oxides ◽  
Supercapacitor Electrode Materials

ABSTRACT The binary metal oxides are increasingly used as supercapacitor electrode materials in energy storing devices. Particularly NiCo2O4 has shown promising electrocapacitive performance with high specific capacitance and energy density. The electrocapacitive performance of these oxides largely depends on their morphology and electrical properties governed by their energy band-gaps and defects. The morphological structure of NiCo2O4 can be altered via the synthesis route, while the energy band-gap could be altered by doping. Also, doping can enhance crystal stability and bring in grain refinement, which can further improve the much-needed surface area for high specific capacitance. Given the above, this study evaluates the electrochemical performance of Ca-doped Ni1-xCaxCo2O4 (0 ≤ x ≤ 0.8) compounds. This stipulates promising applications for electrodes in future supercapacitors.

A Facile Synthesis of NiFe2O4 with High Specific Capacitance as Supercapacitor Electrode Material

2018 ◽  
Vol 281 ◽  
pp. 854-858
Author(s):  
Xi Cheng Gao ◽  
Jian Qiang Bi ◽  
Wei Li Wang ◽  
Guo Xun Sun ◽  
Xu Xia Hao ◽  
...  
Keyword(s):  
Particle Size ◽  
Specific Capacitance ◽  
Electrochemical Property ◽  
Electrode Materials ◽  
High Specific Capacitance ◽  
Constant Current ◽  
X Ray Diffraction ◽  
Supercapacitor Electrode ◽  
Constant Current Charge ◽  
Supercapacitor Electrode Materials

NiFe2O4 powders were synthesized by a facile hydrothermal method at 180°C followed by a thermal treatment at 300°C. The phase composition and morphology were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that the NiFe2O4 powders were well-crystallized, and they possessed a particle size in the range of 50-100 nm. The electrochemical property was characterized via cyclic voltammetry (CV) and constant current charge-discharge method. Encouragingly, the NiFe2O4 powders had an excellent electrochemical property, whose specific capacitance reached 266.84 F/g at the electric current density of 1 A/g due to the small particle size. Compared with other Fe-based metal compound oxides, NiFe2O4 has a better electrochemical performance, which can be widely used in the supercapacitor electrode materials.

scholarly journals Sol-gel synthesis and electrochemical performance of NiCo2O4 nanoparticles for supercapacitor applications

2019 ◽  
Vol 9 (4) ◽  
pp. 243-253
Author(s):  
Yong Zhang ◽  
Yi Ru ◽  
Hai-Li Gao ◽  
Shi-Wen Wang ◽  
Ji Yan ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Electrode Materials ◽  
Retention Rate ◽  
Sol Gel ◽  
High Specific Capacitance ◽  
Supercapacitor Electrode ◽  
Electrochemical Tests ◽  
Potential Electrode ◽  
Current Densities

In this work, NiCo2O4 nanoparticles with enhanced supercapacitive performance have been successfully synthesized via a facile sol-gel method and subsequent calcination in air. The morphology and composition of as-prepared samples were characterized using scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray dif­fraction (XRD), and Raman spectroscopy (Raman). The electrochemical per­formances of NiCo2O4 nanoparticles as supercapacitor electrode materials were evalu­ated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) tests in 3 mol L-1 KOH aqueous solution. The results show that as-prepared NiCo2O4 nanoparticles have diameters of about 20-30 nm with uniform distribution. There are some interspaces between nanoparticles observed, which could increase the effective contact area with the electrolyte and provide fast path for the insertion and extraction of electrolyte ions. The electrochemical tests show that the prepared NiCo2O4 nanoparticles for supercapacitors exhibit excellent electrochemical performance with high specific capacitance and good cycle stability. The specific capacitance of NiCo2O4 electrode has been found as high as 1080, 800, 651, and 574 F g-1 at current densities of 1, 4, 7, and 10 A g-1, respectively. Notably, the capacitance retention rate (compared with 1 A g-1) is up to 74.1 %, 60.3 %, and 53.1 % at current densities of 4, 7, and 10 A g-1, respectively. After 100 cycles, higher capacitance retention rate is also achieved. Therefore, the results indicate that NiCo2O4 material is the potential electrode material for supercapacitors.

scholarly journals Nanoflower Ni(OH)2 grown in situ on Ni foam for high-performance supercapacitor electrode materials

2021 ◽  
Vol 5 (20) ◽  
pp. 5236-5246
Author(s):  
Xuerui Yi ◽  
Huapeng Sun ◽  
Neil Robertson ◽  
Caroline Kirk
Keyword(s):  
Specific Capacitance ◽  
High Performance ◽  
Electrode Materials ◽  
High Specific Capacitance ◽  
Ni Foam ◽  
Supercapacitor Electrode ◽  
Supercapacitor Electrode Materials

Nanoflower Ni(OH)2 shows exceptionally high specific capacitance.

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.

scholarly journals Electrochemical Performance of Aluminum Doped Ni1−xAlxCo2O4 Hierarchical Nanostructure: Experimental and Theoretical Study

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1750
Author(s):  
Deepa Guragain ◽  
Romakanta Bhattarai ◽  
Jonghyun Choi ◽  
Wang Lin ◽  
Ram Krishna Gupta ◽  
...  
Keyword(s):  
Energy Density ◽  
Electrochemical Performance ◽  
Band Gap ◽  
Specific Capacitance ◽  
Surface Area ◽  
Power Density ◽  
High Power ◽  
Energy Band ◽  
High Specific Capacitance ◽  
High Power Density

For electrochemical supercapacitors, nickel cobaltite (NiCo2O4) has emerged as a new energy storage material. The electrocapacitive performance of metal oxides is significantly influenced by their morphology and electrical characteristics. The synthesis route can modulate the morphological structure, while their energy band gaps and defects can vary the electrical properties. In addition to modifying the energy band gap, doping can improve crystal stability and refine grain size, providing much-needed surface area for high specific capacitance. This study evaluates the electrochemical performance of aluminum-doped Ni1−xAlxCo2O4 (0 ≤ x ≤ 0.8) compounds. The Ni1−xAlxCo2O4 samples were synthesized through a hydrothermal method by varying the Al to Ni molar ratio. The physical, morphological, and electrochemical properties of Ni1−xAlxCo2O4 are observed to vary with Al3+ content. A morphological change from urchin-like spheres to nanoplate-like structures with a concomitant increase in the surface area, reaching up to 189 m2/g for x = 0.8, was observed with increasing Al3+ content in Ni1−xAlxCo2O4. The electrochemical performance of Ni1−xAlxCo2O4 as an electrode was assessed in a 3M KOH solution. The high specific capacitance of 512 F/g at a 2 mV/s scan rate, 268 F/g at a current density of 0.5 A/g, and energy density of 12.4 Wh/kg was observed for the x = 0.0 sample, which was reduced upon further Al3+ substitution. The as-synthesized Ni1−xAlxCo2O4 electrode exhibited a maximum energy density of 12.4 W h kg−1 with an outstanding high-power density of approximately 6316.6 W h kg−1 for x = 0.0 and an energy density of 8.7 W h kg−1 with an outstanding high-power density of approximately 6670.9 W h kg−1 for x = 0.6. The capacitance retention of 97% and 108.52% and the Coulombic efficiency of 100% and 99.24% were observed for x = 0.0 and x = 0.8, respectively. First-principles density functional theory (DFT) calculations show that the band-gap energy of Ni1−xAlxCo2O4 remained largely invariant with the Al3+ substitution for low Al3+ content. Although the capacitance performance is reduced upon Al3+ doping, overall, the Al3+ doped Ni1−xAlxCo2O4 displayed good energy, powder density, and retention performance. Thus, Al3+ could be a cost-effective alternative in replacing Ni with the performance trade off.

scholarly journals Natural sliced wood veneer as a universal porous lightweight substrate for supercapacitor electrode materials

RSC Advances ◽  
2017 ◽  
Vol 7 (86) ◽  
pp. 54806-54812 ◽  
Author(s):  
Shaoyi Lyu ◽  
Yanping Chen ◽  
Shenjie Han ◽  
Limin Guo ◽  
Na Yang ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Electrode Materials ◽  
Supercapacitor Electrode ◽  
Wood Veneer ◽  
Active Materials ◽  
Supercapacitor Electrode Materials

We herein report the use of natural sliced wood veneer as a porous lightweight substrate for supercapacitor electrodes, where PANI/RGO and PPy/RGO were employed as active materials, and both wood electrodes showed good electrochemical performance.

Hierarchical Dendritic Polypyrrole with High Specific Capacitance for High-performance Supercapacitor Electrode Materials

2017 ◽  
Vol 20 (4) ◽  
pp. 197-204
Author(s):  
Weiliang Chen ◽  
Shuhua Pang ◽  
Zheng Liu ◽  
Zhewei Yang ◽  
Xin Fan ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
High Performance ◽  
Electrode Materials ◽  
High Specific Capacitance ◽  
Chemical Oxidation ◽  
Channel Structure ◽  
Supercapacitor Electrode ◽  
Infrared Spectrometer ◽  
A Current

Polypyrrole with hierarchical dendritic structures assembled with cauliflower-like structure of nanospheres, was synthesized by chemical oxidation polymerization. The structure of polyryrrole was characterized by Fourier transform infrared spectrometer and scanning electron microscopy. The electrochemical performance was performed on CHI660 electrochemical workstation. The results show that oxalic acid has a significant effect on morphology of PPy products. The hierarchical dendritic PPyOA(3) electrodes possess a large specific capacitance as high as 744 F/g at a current density of 0.2 A/g and could achieve a higher specific capacitance of 362 F/g even at a current density of 5.0 A/g. Moreover, the dendritic PPy products produce a large surface area on the electrode through the formation of the channel structure with their assembled cauliflower-like morphology, which facilitates the charge/electron transfer relative to the spherical PPy electrode. The spherical dendritic PPyOA(3) electrode has 58% retention of initial specific capacitance after 260 cycles. The as-prepared dendritic polypyrrole with high performance is a promsing electrode material for supercapacitor.

Sign in / Sign up

Export Citation Format

Share Document