scholarly journals Synthesis and Characterization of Nickel-doped Manganese Dioxide Electrode Materials for Supercapacitors

2019 ◽  
Vol 79 ◽  
pp. 03002 ◽  
Author(s):  
Jie Dong ◽  
Zhenzhong Hou ◽  
Qiuli Zhao ◽  
Qinghao Yang

Nickel-doped manganese dioxide (Ni-MnO2) synthesized by sol-gel method has been used as an electrode material for supercapacitors. The structure and electrochemical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectrometry (EIS). Results showed that the nickel-doped manganese dioxide sample exhibited irregular particles with the diameter of about 500 nm. The crystallographic structure of MnO2 was the poorly crystallized γ-MnO2. The doping ratio had a great influence on the electrochemical properties of the materials. When the molar ratio of Ni/Mn was 3/100, the specific capacitance of Ni-MnO2 achieved to 252.61 F/g. After 2000 charge/discharge cycles, the specific capacitance of Ni-MnO2 was still maintained at 74.36%, which was attributed to its excellent cycling stability.

2020 ◽  
Vol 16 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Palani Anandhi ◽  
Veerabadran Jawahar Senthil Kumar ◽  
Santhanam Harikrishnan

Background: Of late, supercapacitors have been drawing great attention over other rechargeable energy storage devices. More efforts are made on the electrode materials of the supercapacitors, in order to improve the specific capacitance and energy density. Based on the past literature, it was stated that pure TiO2 (as electrode material) could promote faradaic reaction to a limited extent due to its low electronic conductivity. Further, this low conductivity could hinder the ion transfer process between electrolyte and electrode during intercalation and de-intercalation, resulting in poor energy density. Hence, it is essential to incorporate high electronic conductivity material into TiO2, for improving the electrochemical performance. Objective: In the present study, the preparation and electrochemical performance of NiO/TiO2 nanocomposites as an electrode material for supercapacitor were extensively studied. Methods: NiO/TiO2 nanocomposites were synthesized by sol-gel method. The as-prepared nanocomposites were characterized by high-resolution TEM, field emission SEM and XRD. The electrochemical behaviors of the electrode using nanocomposites were assessed by means of cyclic voltammetry (CV) and galvanostatic charge-discharge tests. Results: The maximum specific capacitance of the nanocomposites based electrode witnessed through CV test was 405 F g-1 at the scan rate of 5 mV s-1 in 1M Na2SO4 electrolyte. The capacitance retention after 5000 charge-discharge cycles was estimated as 92.32%. The energy and power densities at current density of 1 A g-1 were found to be 5.67 Wh kg-1 and 210.52 W kg-1, respectively. Conclusion: NiO/TiO2 nanocomposites synthesized via sol-gel technique appeared to be flake-like structure. NiO incorporated into TiO2 increased higher electronic conductivity while comparing to pure TiO2. Also, an introduction of NiO into TiO2 improved the specific capacitance, power density, energy density and cycle stability. Due to these facts, combining NiO with TiO2 could be considered to be an efficient way of enhancing the electrochemical performance of electrodes of the supercapacitor.


2020 ◽  
Vol 13 (02) ◽  
pp. 2051007
Author(s):  
Jie Dong ◽  
Qinghao Yang ◽  
Qiuli Zhao ◽  
Zhenzhong Hou ◽  
Yue Zhou ◽  
...  

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.


2021 ◽  
Vol 5 (5) ◽  
pp. 129
Author(s):  
Yapeng Wang ◽  
Yanxiang Wang ◽  
Chengjuan Wang ◽  
Yongbo Wang

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.


2017 ◽  
Vol 727 ◽  
pp. 698-704 ◽  
Author(s):  
Xian Wei Wang ◽  
Xiao Er Wang ◽  
Hui Chao Zhang ◽  
Qian Qian Zhu ◽  
Dong Li Zheng ◽  
...  

The structural and electrochemical properties of lanthanum manganate (LaMnO3) powder prepared by the sol-gel method are researched in this article. The powder calcined at 600 °C showed amorphous, and the powder calcined at 700-800 °C showed the pure phase of the LaMnO3. The grains with the size of about 80-120 nm were agglomerating together. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical properties in alkaline environment. The electrochemical properties calcined at 700 °C showed a specific capacitance of 73 F/g at the current density of 0.5 A/g. The raw materials for preparing the LaMnO3 powder are cheap, and the operation method is simple.


Author(s):  
Aqib Muzaffar ◽  
Keerthana Muthusamy ◽  
M. Basheer Ahamed

Ferrous nitrate/nickel oxide {Fe(NO3)2–NiO} nanocomposite was synthesized via two-step facile hydrothermal route. The nanocomposite exhibits crystalline structure as unveiled by X-ray diffraction (XRD) pattern, while as the scanning electron microscope (SEM) images divulge spherical morphologies for both Fe(NO3)2 as well as NiO nanoparticles differentiating from each other in size. Cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques were used to investigate supercapacitive behavior of the symmetrically fabricated nanocomposite electrode configuration using aqueous KOH as the electrolyte. The CV analyses demonstrate dominant electrical double layer capacitance (EDLC) behavior in the potential range of 0–1 V. From charge–discharge curves, the maximum specific capacitance calculated was 460 F g−1 corresponding to the energy density of 16 W h kg−1 at a high power density of 250 W kg−1. EIS data affiliate well with the CV and GCD results justifying the maximum contribution of specific capacitance due to double layer capacitance. The nanocomposite retained 84% of its original capacitance after 1000 cycles and yielded maximum efficiency of 78%.


1999 ◽  
Vol 575 ◽  
Author(s):  
Suh-Cern Pang ◽  
MarcA Anderson

ABSTRACTNanoparticulate MnO2thin films fabricated by the sol-gel process have been shown to be an outstanding novel electrode material for Ultracapacitors. The average specific capacitance of sol-gel-derived MnO2thin-films on nickel substrates as determined by cyclic voltammetry ranged from 566 to 698 F/g. These films also exhibited good cycling stability within the potential range of 0.0-0.9V (vs SCE) in unbuffered aqueous electrolyte. Both CV and XPS studies showed that MnO2films have remained chemically and structurally intact after 1,500 cycles. The XRD spectra and SEM micrographs showed that the microstructure of MnO2thin films are highly porous, and poorly crystalline or amorphous in nature. The high specific capacitance of MnO2may be predominantly due to pseudocapacitance associated with homogenous and reversible redox reactions of proton insertion into and out of the MnO2lattice. Any variation in the microstructure and thickness of films might affect proton mobility within the oxide matrix and thereby affecting their cycling behaviors. Further optimization of the cycling behaviors is envisaged with better microstructural and thickness control of these sol-gelderived nanoparticulate MnO2thin films.


Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 241
Author(s):  
Keishu Miki ◽  
Takeshi Watanabe ◽  
Shinji Koh

In research on enzyme-based biofuel cells, covalent or noncovalent molecular modifications of carbon-based electrode materials are generally used as a method for immobilizing enzymes and/or mediators. However, the influence of these molecular modifications on the electrochemical properties of electrode materials has not been clarified. In this study, we present the electrochemical properties of chemical vapor deposition (CVD)-grown monolayer graphene electrodes before and after molecular modification. The electrochemical properties of graphene electrodes were evaluated by cyclic voltammetry and electrochemical impedance measurements. A covalently modified graphene electrode showed an approximately 25-fold higher charge transfer resistance than before modification. In comparison, the electrochemical properties of a noncovalently modified graphene electrode were not degraded by the modification.


Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 969
Author(s):  
Parnia Forouzandeh ◽  
Vignesh Kumaravel ◽  
Suresh C. Pillai

The advanced electrochemical properties, such as high energy density, fast charge–discharge rates, excellent cyclic stability, and specific capacitance, make supercapacitor a fascinating electronic device. During recent decades, a significant amount of research has been dedicated to enhancing the electrochemical performance of the supercapacitors through the development of novel electrode materials. In addition to highlighting the charge storage mechanism of the three main categories of supercapacitors, including the electric double-layer capacitors (EDLCs), pseudocapacitors, and the hybrid supercapacitors, this review describes the insights of the recent electrode materials (including, carbon-based materials, metal oxide/hydroxide-based materials, and conducting polymer-based materials, 2D materials). The nanocomposites offer larger SSA, shorter ion/electron diffusion paths, thus improving the specific capacitance of supercapacitors (SCs). Besides, the incorporation of the redox-active small molecules and bio-derived functional groups displayed a significant effect on the electrochemical properties of electrode materials. These advanced properties provide a vast range of potential for the electrode materials to be utilized in different applications such as in wearable/portable/electronic devices such as all-solid-state supercapacitors, transparent/flexible supercapacitors, and asymmetric hybrid supercapacitors.


2020 ◽  
Vol 20 (8) ◽  
pp. 4854-4859 ◽  
Author(s):  
Lei Chen ◽  
Xu Chen ◽  
Yaqiong Wen ◽  
Bixia Wang ◽  
Yangchen Wu ◽  
...  

Nitrogen-enriched reduced graphene oxide electrode material can be successfully prepared through a simple hydrothermal method. The morphology and microstructure of ready to use electrode material is measured by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). Physical characterizations revealed that nitrogen-enriched reduced graphene oxide electrode material possessed high specific surface area of 429.6 m2 · g−1, resulting in high utilization of electrode materials with electrolyte. Electrochemical performance of nitrogen-enriched reduced graphene oxide electrode was also investigated by cyclic voltammetry (CV), galvanostatic charge/discharge measurements and electrochemical impedance spectroscopy (EIS) in aqueous in 6 M KOH with a three-electrode system, which displayed a high specific capacitance about 223.5 F · g−1 at 1 mV · s−1. More importantly, nitrogenenriched reduced graphene oxide electrode exhibited outstanding stability with 100% coulombic efficiency and with no specific capacitance loss under 2 A · g−1 after 10000 cycles. The supercapacitive behaviors indicated that nitrogen-enriched reduced graphene oxide can be a used as a promising electrode for high-performance super-capacitors.


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