scholarly journals Electrochemical Performance of Iron-Doped Cobalt Oxide Hierarchical Nanostructure

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2176
Author(s):  
Deepa Guragain ◽  
Sunil Karna ◽  
Jonghyun Choi ◽  
Romakanta Bhattarai ◽  
Tej P. Poudel ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Cobalt Oxide ◽  
Water Splitting ◽  
Current Density ◽  
Density Functional ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Iron Doped ◽  
A Current

In this study, hydrothermally produced Fe-doped Co3O4 nanostructured particles are investigated as electrocatalysts for the water-splitting process and electrode materials for supercapacitor devices. The results of the experiments demonstrated that the surface area, specific capacitance, and electrochemical performance of Co3O4 are all influenced by Fe3+ content. The FexCo3-xO4 with x = 1 sample exhibits a higher BET surface (87.45 m2/g) than that of the pristine Co3O4 (59.4 m2/g). Electrochemical measurements of the electrode carried out in 3 M KOH reveal a high specific capacitance of 153 F/g at a current density of 1 A/g for x = 0.6 and 684 F/g at a 2 mV/s scan rate for x = 1.0 samples. In terms of electrocatalytic performance, the electrode (x = 1.0) displayed a low overpotential of 266 mV (at a current density of 10 mA/cm2) along with 52 mV/dec Tafel slopes in the oxygen evolution reaction. Additionally, the overpotential of 132 mV (at a current density of 10 mA/cm2) and 109 mV with 52 mV/dec Tafel slope were obtained for x = 0.6 sample towards hydrogen evolution reaction (HER). According to electrochemical impedance spectroscopy (EIS) measurements and the density functional theory (DFT) study, the addition of Fe3+ increased the conductivity at the electrode–electrolyte interface, which substantially impacted the high activity of the iron-doped cobalt oxide. The electrochemical results revealed that the mesoporous Fe-doped Co3O4 nanostructure could be used as potential electrode material in the high-performance electrochemical capacitor and water-splitting catalysts.

scholarly journals A Hierarchical Architecture of Functionalized Polyaniline/Manganese Dioxide Composite with Stable-Enhanced Electrochemical Performance

2021 ◽  
Vol 5 (5) ◽  
pp. 129
Author(s):  
Yapeng Wang ◽  
Yanxiang Wang ◽  
Chengjuan Wang ◽  
Yongbo Wang
Keyword(s):  
Electrochemical Performance ◽  
Manganese Dioxide ◽  
Specific Capacitance ◽  
Current Density ◽  
Electrode Materials ◽  
High Efficiency ◽  
Scanning Speed ◽  
Hierarchical Architecture ◽  
Electrochemical Window ◽  
A Current

As one of the most outstanding high-efficiency and environmentally friendly energy storage devices, the supercapacitor has received extensive attention across the world. As a member of transition metal oxides widely used in electrode materials, manganese dioxide (MnO2) has a huge development potential due to its excellent theoretical capacitance value and large electrochemical window. In this paper, MnO2 was prepared at different temperatures by a liquid phase precipitation method, and polyaniline/manganese dioxide (PANI/MnO2) composite materials were further prepared in a MnO2 suspension. MnO2 and PANI/MnO2 synthesized at a temperature of 40 °C exhibit the best electrochemical performance. The specific capacitance of the sample MnO2-40 is 254.9 F/g at a scanning speed of 5 mV/s and the specific capacitance is 241.6 F/g at a current density of 1 A/g. The specific capacitance value of the sample PANI/MnO2-40 is 323.7 F/g at a scanning speed of 5 mV/s, and the specific capacitance is 291.7 F/g at a current density of 1 A/g, and both of them are higher than the specific capacitance value of MnO2. This is because the δ-MnO2 synthesized at 40 °C has a layered structure, which has a large specific surface area and can accommodate enough electrolyte ions to participate the electrochemical reaction, thus providing sufficient specific capacitance.

Integration of mesoporous nickel cobalt oxide nanosheets with ultrathin layer carbon wrapped TiO2 nanotube arrays for high-performance supercapacitors

2016 ◽  
Vol 40 (8) ◽  
pp. 6881-6889 ◽  
Author(s):  
Cuiping Yu ◽  
Yan Wang ◽  
Jianfang Zhang ◽  
Xia Shu ◽  
Jiewu Cui ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Cobalt Oxide ◽  
Current Density ◽  
High Performance ◽  
Tio2 Nanotube Arrays ◽  
Nanotube Arrays ◽  
Nickel Cobalt ◽  
Nickel Cobalt Oxide ◽  
A Current ◽  
Ultrathin Layer

Novel nanocomposite NiCo2O4/C-TNAs were synthesized for high-performance supercapacitors with a specific capacitance of 934.9 F g−1 at a current density of 2 A g−1.

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.

High-performance overall water splitting based on amorphous iron doped cobalt tungstate via facile co-precipitation

2021 ◽  
Vol 9 (15) ◽  
pp. 9753-9760
Author(s):  
Jin Wu ◽  
Renjie Xie ◽  
Xiangchen Hu ◽  
Zhiwei Nie ◽  
Yanuo Shi ◽  
...  
Keyword(s):  
Water Splitting ◽  
Current Density ◽  
High Performance ◽  
Amorphous Iron ◽  
Bifunctional Electrocatalyst ◽  
Overall Water Splitting ◽  
Iron Doped ◽  
Cobalt Tungstate ◽  
Co Precipitation ◽  
A Current

The as-prepared amorphous Fe-doped CoWO4 bifunctional electrocatalyst shows a low overpotential of 259 and 118 mV to reach a current density of 10 mA cm−2 for the OER and HER in 1 M KOH, respectively.

Co3S4/NiCo2S4 Nano-Arrays on Nickel Foam as Energy Storage for Supercapacitors

2021 ◽  
Vol 16 (6) ◽  
pp. 891-904
Author(s):  
Xiang-Sen Meng ◽  
Jun Xiang ◽  
Nan Bu ◽  
Yan Guo ◽  
Sroeurb Loy ◽  
...  
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Current Density ◽  
Retention Rate ◽  
Nickel Foam ◽  
Maximum Energy ◽  
Capacity Retention ◽  
A Current

In this work, Co3S4/NiCo2S4 nano-arrays electrode with Co3S4 nanocones and NiCo2S4 nanosheets interlaced arrangement are prepared by the promising hydrothermal method. Compared with single Co3S4/NF or NiCo2S4/NF electrode, the prepared Co3S4/NiCo2S4/NF electrode exhibits excellent specific capacitance. At a current density of 2 mA cm−2, the surface capacitance is as high as 9036 mF cm−2, and it still maintains a surface capacitance of 5664 mF cm−2 at a current density of 8 mA cm−2. Co3S4/NiCo2S4/NF||ASC has a high electrochemical performance with a maximum energy density of 0.62 Wh cm−3 and a power density of 15.94 W cm−3. At a current density of 5 mA cm−2, the capacity retention rate is 83.75% after 3000 cycles.

scholarly journals Preparation of Porous Activated Carbons for High Performance Supercapacitors from Taixi Anthracite by Multi-Stage Activation

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3588 ◽  
Author(s):  
Xiao-Ming Yue ◽  
Zhao-Yang An ◽  
Mei Ye ◽  
Zi-Jing Liu ◽  
Cui-Cui Xiao ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
High Performance ◽  
Electrode Materials ◽  
Activated Carbons ◽  
High Rank ◽  
Cycle Performance ◽  
Electrochemical Performances ◽  
Multi Stage ◽  
A Current

Coal-based porous materials for supercapacitors were successfully prepared using Taixi anthracite (TXA) by multi-stage activation. The characterization and electrochemical tests of activated carbons (ACs) prepared in different stages demonstrated that the AC from the third-stage activation (ACIII) shows good porous structures and excellent electrochemical performances. ACIII exhibited a fine specific capacitance of 199 F g−1 at a current density of 1 A g−1 in the three-electrode system, with 6 mol L−1 KOH as the electrolyte. The specific capacitance of ACIII remained 190 F g−1 even despite increasing the current density to 5 A g−1, indicating a good rate of electrochemical performance. Moreover, its specific capacitance remained at 98.1% of the initial value after 5000 galvanostatic charge-discharge (GCD) cycle tests at a current density of 1 A g−1, suggesting that the ACIII has excellent cycle performance as electrode materials for supercapacitors. This study provides a promising approach for fabricating high performance electrode materials from high-rank coals, which could facilitate efficient and clean utilization of high-rank coals.

Surface Phosphation of 3D NiCo2O4 Nanowires Grown on Ni Foam as an Efficient Bifunctional Catalyst for Water Splitting

NANO ◽  
2020 ◽  
Vol 15 (02) ◽  
pp. 2050024 ◽  
Author(s):  
Lanzi Cheng ◽  
Rui Zhang ◽  
Weixin Lv ◽  
Luyu Shao ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Water Splitting ◽  
Current Density ◽  
Electrode Materials ◽  
Catalyst Activity ◽  
Cell Voltage ◽  
Cost Effective ◽  
Bifunctional Catalyst ◽  
P Element ◽  
Ni Foam

Highly efficient, cost-effective and durable electrocatalysts for water splitting are crucial for energy conversion and storage. Transition-metal phosphides have been proven to be efficient catalysts for water splitting. In this paper, surface phosphation of 3D NiCo2O4 nanowires grown on Ni foam (P-NiCo2O4/NF) have been prepared to investigate the effect of surface phosphating on catalyst activity. XRD and XPS results demonstrate that P element has been decorated on the surface of the NiCo2O4 nanowires. The electrochemical results prove that P-NiCo2O4/NF shows better electrochemical performance than pure NiCo2O4/NF as an electrode for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) of water splitting. It achieves a current density of 10[Formula: see text]mA cm2 at an overpotential of 279[Formula: see text]mV and 164[Formula: see text]mV for OER and HER in 1.0[Formula: see text]M KOH electrolyte, respectively. In addition, the P-NiCo2O4/NF[Formula: see text]P-NiCo2O4/NF electrode is constructed by employing P-NiCo2O4/NF as both the anode and cathode, it only requires a low 1.68[Formula: see text]V of cell voltage to reach the current density of 10[Formula: see text]mA cm[Formula: see text]. Notably, P-NiCo2O4/NF[Formula: see text]P-NiCo2O4/NF also exhibits excellent stability for over 30[Formula: see text]h-long. These results indicate that surface phosphation is an effective approach to improve the electrochemical performance of NiCo2O4/NF electrode materials.

One-Step Hydrothermal Preparation of 1D α-MoO3 Nanobelt Electrode Material for Supercapacitor

NANO ◽  
2019 ◽  
Vol 14 (07) ◽  
pp. 1950085 ◽  
Author(s):  
Puhong Wen ◽  
Jingjing Guo ◽  
Lijun Ren ◽  
Chuanchuan Wang ◽  
Yuzhu Lan ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Current Density ◽  
Electrode Material ◽  
High Specific Capacitance ◽  
Raw Material ◽  
Hydrothermal Preparation ◽  
Ammonium Heptamolybdate ◽  
One Step ◽  
A Current

1D [Formula: see text]-MoO3 nanobelts were prepared using ammonium heptamolybdate tetrahydrate [(NH[Formula: see text]Mo7O[Formula: see text]H2O] as raw material by one-step hydrothermal method without template or guide agent at 180∘C. The layered [Formula: see text]-MoO3 nanobelt electrode has favorable electrochemical performance, and displays a fairly high specific capacitance, which can be up to 445[Formula: see text]F/g at a current density of 0.5[Formula: see text]A/g.

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.

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