Electrochemical properties of microwave-assisted reflux-synthesized Mn3O4 nanoparticles in different electrolytes for supercapacitor applications (original) (raw)
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Synthesis of Mn3O4 nanoparticles via chemical precipitation approach for supercapacitor application
Journal of Alloys and Compounds, 2015
A simple chemical precipitation method has been used for the preparation of Mn 3 O 4 nanoparticles at room temperature. The crystal structure and morphology studies of the resulting Mn 3 O 4 nanoparticles were characterized by powder X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), N 2 adsorption and desorption and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of the Mn 3 O 4 nanoparticles were then investigated using cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) analysis. The supercapacitive properties of Mn 3 O 4 nanoparticles in the presence of 1 M Na 2 SO 4 exhibited a high specific capacitance of 322 F g À1 at a current density of 0.5 mA cm À2 in the potential range from À0.1 to +0.9 V and about 77% of the initial capacitance was retained after 1000 cycles, indicating that the Mn 3 O 4 electrode owns a good electrochemical stability and capacitance retention capability. The results suggest that the obtained Mn 3 O 4 nanoparticles is a promising electrode material for supercapacitor applications.
International Journal of Scientific Research in Science and Technology, 2021
Mn3O4 and its composite nanomaterials have become promising candidate as an electrode for supercapacitor devices, because of its low cost, non-toxicity, large abundance, high porosity and high capacitance values in aqueous electrolyte. Here, we systematically summarized the impact of different morphologies of Mn3O4 and its composite nanomaterials on supercapacitive performance. Many researchers synthesized various Mn3O4 and its composite nanomaterials of exceptional properties and different morphologies for energy storage. This article reviews recent efforts and developments in synthesis methods Mn3O4 and its composite nanomaterials as an electrode material in supercapacitor.
Applied Surface Science, 2012
Spherical Mn 3 O 4 nanoparticles were synthesized by microwave assisted reflux method at different reaction times (1, 5, 10, 15, and 20 min). The single phase formation of Mn 3 O 4 nanoparticles was identified through XRD analysis. The FT-IR and Raman spectra revealed the presence of functional groups of Mn 3 O 4 and further support the XRD results. The spherical morphology of Mn 3 O 4 was identified via SEM analysis. The cyclic voltammetry analysis implies that 15 min synthesized Mn 3 O 4 (MN-15) shows the higher specific capacitance of 135 F g −1 among all the prepared Mn 3 O 4 electrodes. The EIS spectra of MN-15 substantiate the less charge-transfer resistance (R ct) of 0.553 , when compared with the other samples. The discharge capacitance of MN-15 was 103 F g −1 at 0.5 mA cm −2 in 1 M NaNO 3 solution. The cycling stability curve over 100 cycles implies that the discharge capacitance is increased from 47 to 68 F g −1 at 5 mA cm −2. This capacitance enhancement during cycling is due to the influence of phase or morphological variation of Mn 3 O 4 electrodes.
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.
Supercapacitive properties of Mn3O4 nanoparticles bio-synthesized from banana peel extract
RSC Advances, 2014
Mn 3 O 4 nanoparticles have been successfully synthesized by a simple hydrothermal method at low temperature. The microstructural and electrochemical properties are studied. The XRD data exhibited (211) predominant orientation structure of Mn 3 O 4 with I4 1 /amd(141) space group and an estimated crystallite size of 65 nm. The SEM analysis reveals that the average grain size is 200 nm. The vibrational studies from Raman and FTIR measurements confirmed the presence of Mn-O bonding. The Mn 3 O 4 nanoparticles exhibited high specific capacitance of 198 Fg-1 at a current density of 0.5 mAcm-2 in 0.5M Li 2 SO 4 aqueous electrolyte. The Mn 3 O 4 electrode retained up to 70% of initial capacitance even after 1000 cycles exhibiting good electrochemical stability and capacitance retention capability. These results suggest that the obtained Mn 3 O 4 nanoparticles are the better candidate for supercapacitor applications.
Improved electrochemical performance of Mn3O4 thin film electrodes for supercapacitors
Materials Science in Semiconductor Processing, 2018
Fabrication of the Mn 3 O 4 thin film electrodes is an important area of research for the development of supercapacitors. Investigations were made to improve the electrochemical properties of the electron beam evaporated Mn 3 O 4 films. The films grown on stainless steel substrates at a substrate temperature of 473 K with subsequent annealing at 573 K for 4 h were in a single phase, which corresponds to the tetragonal structure of Mn 3 O 4 with I41/amd (141) space group. The Raman studies were also confirmed the single phase of Mn 3 O 4 films. The AFM data revealed that the surface of the films covered with dispersed vertical grains of size 36 nm with the rms surface roughness of 18 nm. The SEM image displayed the flower like growth of Mn 3 O 4 on the substrate. The films deposited at 573 K exhibited a specific capacitance of 568 F g −1 at a current density of 1 A g −1 in 1 M Na 2 SO 4 aqueous electrolyte with excellent capacitance retention of 93% even after 5000 cycles. The films annealed above 600 K were found to have mixed phases and corresponding capacitance decreased with annealing temperatures. The films annealed at 773 K exhibited only Mn 2 O 3 phase with a lower specific capacitance of 240 F g −1 .
Microwave-Assisted Synthesis and Characterization of γ-MnO2 for High-Performance Supercapacitors
Journal of Electronic Materials, 2021
Two hydrothermal techniques under microwave irradiation were used to synthesize γ-MnO2 from 90°C to 150°C in 10−30 min. The first technique is based on reducing KMnO4 with MnSO4, and the second one involves liquid-phase oxidation between MnSO4 and (NH4)2S2O8. The structures and morphologies of the samples were analyzed using X-ray diffraction, scanning electron microscopy, and N2 physisorption measurements. The electrochemical properties were evaluated through cyclic voltammetry and electrochemical impedance spectroscopy. The γ-MnO2 materials obtained by the first technique mainly exhibited nanorods with diameters of 40–60 nm, and the samples obtained by the second technique showed flower-like microspheres with diameters of 1−2 µm; each flower was composed of nanosheets with a thickness of 10−20 nm. The processing time directly depends on the size of the nanorods. The sample synthesized by the first technique at 150°C and 10 min has the highest specific surface area of up to 59.08 m...
Sonochemically synthesized MnO2 nanoparticles as electrode material for supercapacitors
2013
In this study, manganese oxide (MnO 2 ) nanoparticles were synthesized by sonochemical reduction of KMnO 4 using polyethylene glycol (PEG) as a reducing agent as well as structure directing agent under room temperature in short duration of time and characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), Transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis. A supercapacitor device constructed using the ultrasonically-synthesized MnO 2 nanoparticles showed maximum specific capacitance (SC) of 282 Fg À1 in the presence of 1 M Ca(NO 3 ) 2 as an electrolyte at a current density of 0.5 mA cm À2 in the potential range from 0.0 to 1.0 V and about 78% of specific capacitance was retained even after 1000 cycles indicating its high electrochemical stability.
Journal of Materials Science: Materials in Electronics, 2016
A new approach has been proposed for the preparation of nanostructured a-MnO 2. The method is based on the galvanostatic cathodic electrodeposition of the product from a nitrate bath under a direct current mode at a current density of 0.1 mA cm-2. The intermediate product deposited in this stage is next thermally treated at 300°C for 3 h. To evaluate the properties of the final product, it was characterized by XRD and FTIR so as to gain information on its phase composition (which was found to be mainly a-MnO 2) and SEM to gain information on its morphology (which was found to be nanospheres with secondary porous wall-like nanostructures). Additional electrochemical experiments on the product through cyclic voltammetry and charge-discharge tests revealed it to be capable of delivering high specific capacitance of 280 F g-1 , further its outstandingly long-term cycling stability which was only diminished to 95.4 % of the initial value after 1000 discharge cycles.
Electrochemical capacitor study of spherical MnO2 nanoparticles utilizing neutral electrolytes
Frontiers in Nanoscience and Nanotechnology, 2015
In this study, we report the synthesis of spherical MnO 2 nanoparticles using spray pyrolysis method. The synthesized particles were characterized by powder X-ray diffraction, Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The SEM image showed spherical nanoparticles with average size of 65 nm, which was in agreement with the TEM measurement. The results of the N2 adsorption-desorption analysis indicated that the BET surface area of the spherical nanoparticles was 102 m 2 g-1 with the pore size diameter of 15.18 nm. The electrochemical measurements such as cyclic voltammetry and electrochemical impedance spectroscopy were made in the solution of 0.1 M Li 2 SO 4 and Na 2 SO 4 electrolytes. At lower scan rates the Na 2 SO 4 electrolyte showed a maximum specific capacitance of 68 F g-1 whereas in the Li2SO4 electrolyte it was found to be 63 F g-1. Moreover, Nyquist plot revealed that Na 2 SO 4 electrolyte had a lower charge transfer resistance (Rct) value when compared to Li 2 SO 4 electrolyte.