beta phase manganese dioxide nanorods Synthesis and characterization for supercapacitor applications (original) (raw)
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Studies on MnO2 Nanorods and Their Application for Supercapacitor
Current Nanomaterials, 2017
Background: Recently, manganese dioxide (MnO 2) has attracted renewed attention of investigators. This is primarily due to its low cost, making it a potential material for various applications. Objective: The goal of the present work was to synthesize MnO 2 nanorods and study their optical and electrochemical properties. Method: The method involves refluxing of potassium permanganate (KMnO 4) and manganese chloride (Mncl 2) mixture in isopropyl alcohol (IPA)-water system. The surface morphology, vibrational response and structural parameters were characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman Spectroscopy, Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and BET surface area measurements. The optical properties of the synthesized material were investigated using PL and UV-Vis. Spectroscopy. Electrochemical properties of resulting product (as an electrode) were studied in two-electrode cell assembly, employing galvanostatic charge/discharge (GCD), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) techniques. Results: FESEM and TEM images show that material is in the form of nanorods. XRD analysis showed the tetragonal structure of synthesized product. Thermal stability up to 400 °C has been observed for the sample. The BET analysis of the sample showed the existence of large and small pores. A direct band-gap of 4.1 eV was observed. Specific capacitance of value 108.2 F g-1 was measured for 1 M Na 2 SO 4 electrolyte solution, at current density of 1 mA cm-2. Conclusion: MnO 2 nanorods were successfully prepared using chemical refluxing technique. The electrochemical studies show that MnO 2 can be profitably used for energy storage applications.
2016
MnO2 is considered as a candid material for supercapacitor applications owing to its varied oxidation states, environmental friendliness and low cost. α-MnO2 nanorods is synthesized by a facile hydrothermal method and is characterized by X-ray Diffraction, Field Emission Scanning Electron Microscopy, gas adsorption studies, cyclic voltammetry, Galvanostatic charge-discharge studies and Electrochemical impedance spectroscopy. The α-MnO2 demonstrated a promising specific capacitance of ~310 F g-1 at a current density of 1 A g-1 with lower contact resistance in 3M LiOH
Manganese oxides are important materials with a variety of applications in different fields such as chemical sensing devices, magnetic devices, field-emission devices, catalysis, ion-sieves, rechargeable batteries, hydrogen storage media and microelectronics. To open up new applications of manganese oxides, novel morphologies or nanostructures are required to be developed. Via sol-gel and anodic electrodeposition methods, M (Co, Fe) doped manganese oxides were prepared. On the other hand, nanostructured (nanoparticles, nanorods and hollow nanotubes) manganese oxides were synthesized via a process including a chemical reaction with carbon nanotubes (CNTs) templates followed by heat treatment. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV) and impedance spectroscopy (EIS) were used for characterization of the prepared materials. The influence of chemical reaction conditions, heat treatment and template present on the morphology, structure, chemical and electrochemical properties of the prepared materials were investigated. Chronopotentiometry (CP) and CV results show high specific capacitance of 186.2 to 298.4 F g −1 and the charge/discharge stability of the prepared materials and the ideal pseudocapacitive behaviors were observed. These results give an opening and promising application of these materials in advanced energy storage applications.
2021
Mn2O3 is a significant candidate for various applications. In the present work, the Mn2O3 nanorod arrays have been successfully prepared through facile sonochemical method with the aid of cetyl trimethyl ammonium bromide (CTAB) template. The crystalline phase and bonding properties have ben confirmed through X-ray diffraction analysis (XRD) and Fourier transform infrared (FTIR) spectroscopic analysis. The electrochemical properties were analysed through various techniques such as cyclic voltammetric and galvanostatic charge/discharge analysis. Interestingly, cyclic voltammetric (CV) curves confirms the electric double layer capacitor-based charge storage mechanism and it render the maximum specific capacitance of 647 Fg-1 at a scan rate 5 mVs-1 whereas the galvanostatic charge/discharge studies offer the specific capacitance of 656 Fg-1 at a current density of 1 Ag-1. The Mn2O3 nanorod arrays provide the maximum energy and power densities of 91.1 Wh Kg-1 and 14985 Wkg-1 respectively...
High-efficiency super capacitors based on hetero-structured α–MnO2 nanorods
Hetero-structured manganese dioxide nanorods with α phase (α–MnO2) were prepared by a facile hydrothermal route at low temperature. X–ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption–desorption measurements were used to characterize the properties of prepared hetero-structured α–MnO2 nanorods. Supercapacitive performance of the hetero-structured α–MnO2 nanomaterials as active electrode material was evaluated by cyclic voltammetry (CV) in alkaline media. The MnO2 hetero-structure with 2 x 2 tunnels constructed from double chains of octahedral [MnO6] structure yield a significantly high specific capacitance of 298 Fg-1 at 5mVs-1 and demonstrated a superior long term cyclic stability, with specific capacitance retention about 94% after 1000 cycles. The superior supercapacitive performance of the hetero-structured α–MnO2 electrode is due to its high specific surface area and unique hierarchy architecture which facilitate fast electron and ion transport.
Applied Physics A, 2021
Mn 2 O 3 is a significant candidate for various applications. In the present work, the Mn 2 O 3 nanorods have been successfully prepared through a facile sonochemical method with the aid of a cetyl trimethyl ammonium bromide (CTAB) template. Systematic analyses were done to confirmes the formation and morphological properties of the Mn 2 O 3 materials. It exhibits superior supercapacitor behavior with an electric double layer capacitor-based charge storage mechanism. The freshly prepared Mn 2 O 3 nanorods render the maximum specific capacitance of 647 Fg −1 at a scan rate of 5 mVs −1, whereas the galvanostatic charge/discharge studies offer the specific capacitance of 656 Fg −1 at a current density of 1 Ag −1. The Mn 2 O 3 nanorods provide the maximum energy and power densities of 91.1 Wh Kg −1 and 1525 Wkg −1, respectively. In addition, the cyclic stability analysis exhibits only 12% initial capacitance degradation over 3000 CV cycles at a scan rate of 100 mVs −1. The hopeful outcomes demonstrate the significance of the Mn 2 O 3 nanorods as electrode material for supercapacitor devices.
Diamond and Related Materials, 2019
The fabrication of energy storage devices with lowering the cost and improving the performance has always been the need for society. Therefore, supercapacitors with special features such as lightweight , easy portability and remarkable charging/discharging rate capability have widely been studied in the literature. In the present work, In-situ carbon coated manganese oxide nanorods (ISCC-MnO 2 NRs) have been studied for the supercapacitor application. ISCC-MnO 2 NRs were prepared by slip casting method followed by annealing at 1200°C. During heat treatment, sucrose has transformed into conducting carbon and coated on the surface of MnO 2. ISCC-MnO 2 NRs were examined by FEG-SEM, FEG-TEM, XRD, FT-IR, BET and Raman spectroscopy. The measurement of the electrochemical properties of the material was carried out in the two-electrode configuration using 1 M Na 2 SO 4 aqueous solution as an electrolyte. The specific capacitance of ISCC-MnO 2 NRs was found to be 28.24 F/g at the current density of 1 A g −1 with energy density of 0.98 Wh/kg. This work suggests ISCC-MnO 2 NRs may be a promising electrode material for the supercapacitor.
International Journal of Electrochemical Science, 2018
High purity α-MnO 2 rectangular nanowires are synthesized by a facile one-step hydrothermal method. The morphology and composition of α-MnO 2 nanowires are characterized by X-ray diffraction, energy-dispersive X-ray spectroscopy (EDX), Field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectral techniques. The electrochemical properties of α-MnO 2 nanowires have been studied as electrode material for supercapacitors. The α-MnO 2 nanowires exhibit a high specific capacitance of 362 Fg-1 at a current density of 1.0 Ag-1 with a good cycling stability (maintained 83% after 5000 cycles). These results indicate its promising applications as a high-performance electrode material for electrochemical energy storage.
Low temperature hydrothermal synthesis of nano-sized manganese oxide for supercapacitors
Electrochimica Acta, 2012
The nano-structured manganese oxide was synthesized by a simple hydrothermal route at a very low temperature of 60 • C using potassium permanganate as oxidant and ethanol as reductant. The structure and surface morphology of the as-prepared manganese oxide were characterized by means of X-ray diffraction and scanning electron microscopy. The obtained manganese oxide was of amorphous and spherical with a particle size of about 100 nm. The capacitive characteristics of the nano-structured manganese oxide electrodes were investigated by means of cyclic voltammetry and galvanostatic charge-discharge cycling in 1 M Na 2 SO 4 . The manganese oxide exhibited not only a maximum specific capacitance of 198 F g −1 , but also excellent rate capability and good cycle stability.
Nanometer-scale particles of MnO2 have been synthesized by microemulsion route for electrochemical supercapacitor studies. The MnO2 has been found to be in -cyrstallographic form with tetragonal unit cell. Particles in the spherical/hexagonal shape with about 50 nm size have been observed in scanning electron microscopy and transmission electron microscopy studies. Cyclic voltammograms have exhibited rectangular shape between 0 and 1.0 V vs saturated calomel electrode at sweep rates up to 100 mV s−1 due to nanoparticles of MnO2. From galvanostatic charge-discharge studies, specific capacitance of 297 F g−1 has been obtained, which is greater than about 240 F g−1 usually reported for this material. The -MnO2 samples have been annealed at several temperatures, and nanoparticles 10–90 nm and nanorods 5 nm diameter of varying dimensions have been obtained. The effect of annealing at different temperatures on crystallographic nature and electrochemical properties are reported.