scholarly journals One−Step Synthesis of Popcorn−Carbon/Co3O4 Composites as High−Performance Supercapacitor Electrodes

Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 76
Author(s):  
Ruiyu Wang ◽  
Mengfan Zhang ◽  
Hao Xu ◽  
Shuo Guo ◽  
Mengqi Chi ◽  
...  

In this study, a novel assisted liquid−phase plasma electrolysis was developed to realize one−step synthesis of popcorn biomass−derived porous carbon/cobalt tetroxide (popcorn−carbon/Co3O4) composites, effectively improving the structural stability and conductivity of Co3O4. The phase structure, morphologies, chemical composition, and weight ratio of the as−prepared popcorn−carbon/Co3O4 composites were systematically analyzed. The results of X−ray diffraction (XRD), Raman spectrometer, Fourier infrared spectrometer (FTIR), X−ray photoelectron spectrometer (XPS), and thermogravimetry analyzer (TG) proved the synthesis of the popcorn−carbon/Co3O4 composites. Co3O4 nanoparticles were distributed relatively uniformly on the popcorn−carbon surface. The electrochemical properties of the popcorn−carbon/Co3O4 composite electrode materials were analyzed for exploring the influence of different Co/C ratios on the electrochemical properties of composites. The results showed that the popcorn−carbon/Co3O4 composite electrode materials prepared under 200:1 mass ratio of Co(NO3)2·6H2O and popcorn−carbon possessed a specific capacitance and specific capacity of almost 1264 F/g (594 C/g) at a current density of 1 A/g, exhibiting a better electrochemical property. The efficient, fast, and novel assisted liquid−phase plasma electrolysis provides a new method for the preparation of composite electrode materials on the supercapacitors.

2020 ◽  
Vol 999 ◽  
pp. 21-27 ◽  
Author(s):  
Yue Zhou ◽  
Qing Hao Yang ◽  
Jie Dong

Nickel-doped manganese dioxide (Ni-MnO2) as electrode materials for supercapacitors were successfully prepared by one-step chemical liquid phase coprecipitation with the different nickel doped proportions. X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray fluorescence (XRF) were used to analyze the micro-structure, morphology and composition. And electrochemical properties were studied by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectrometry (EIS). The results revealed that MnO2 synthesized in this work turned out to be δ-MnO2 of homogeneous dispersion and excellent electrochemical properties. Specific capacitance of 300.85 F/g was achieved for the 2% Ni-doped MnO2 at 2mV/s through cyclic voltammetry, and after 5000 circles the persistence rate of which still remained to 75%, exhibiting a preeminent advantage of stability and reversibility to naked MnO2.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yinghui Han ◽  
Le Li ◽  
Yunpeng Liu ◽  
Xue Li ◽  
Xiaohan Qi ◽  
...  

A simple and efficient process method for the preparation of strontium bismuth oxides (SBOs) via an impregnation-calcination method is presented. The synthesized active materials are characterized using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The electrochemical performance of the as-synthesized SBO samples is observed to decrease gradually as the strontium content is increased from 25% to 50%. The SBO sample with a Sr/Bi ratio of 1 : 3 shows the highest specific capacitance of 1228.7 F g−1 (specific capacity of 204.8 mAh g−1) at a current density of 1 A g−1 and a good cycling stability (75.1%) over 3000 charge-discharge cycles. The improved performance of the supercapacitors can be attributed to the unique structural features resulting from the addition of appropriate portions of Sr, which supports high electron conductivity and rapid ion/electron transport within the electrode and at the electrode/electrolyte interface. All the results show that the SBOs have considerable potential for use as high-performance battery-type electrodes in supercapacitors.


2018 ◽  
Vol 386 ◽  
pp. 359-364
Author(s):  
Yury M. Nikolenko ◽  
Denis P. Opra ◽  
Alexander K. Tsvetnikov ◽  
Alexander Yu. Ustinov ◽  
Valery G. Kuryavyi ◽  
...  

The hydrolytic lignin derivatives have been prepared via its physical activation (high-temperature heating in vacuum) followed by chemical modification (fluorination). The obtained products were characterized using scanning electron microscopy, X-ray diffraction, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. It was found that the graphitized product of thermal activation up to 1000 °C at a low rate of < 2 °C/min under high vacuum shows an enhanced specific surface area (215 m2/g), that makes its potentially useful as sorbent, catalytic substrate or electrode material. To clarify the potentialities of hydrolytic lignin derivatives for energy storage and conversion, the electrochemical system with metallic lithium anode was applied. The galvanostatic discharge of battery at a current density of 100 μA/cm2between 3.0 and 0.5 V shows that the specific capacity of thermally activated derivative is equal to 845 mA·h/g, while the untreated lignin yields only 190 mA·h/g. The improve of the electrochemical performance of product originates from its graphitization, increasing electronic conductivity, and, possibly, enhanced ability to adsorb of oxygen. The fluorination of both the lignin and its thermally activated form results in higher operating voltage of battery, as seems, due to the involvement of fluorine bound to carbon in electrochemical process.


Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 126 ◽  
Author(s):  
Pei-Chi Cheng ◽  
Bing-Han Li ◽  
Feng-Shuen Tseng ◽  
Po-Ching Liang ◽  
Chia-Her Lin ◽  
...  

Four lithium coordination polymers, [Li3(BTC)(H2O)6] (1), [Li3(BTC)(H2O)5] (2), [Li3(BTC)(μ2-H2O)] (3), and [Li(H2BTC)(H2O)] (4) (H3BTC = 1,3,5-benzenetricarboxylatic acid), have been synthesized and characterized. All the structures have been determined using single crystal X-ray diffraction studies. Complexes 1 and 2 have two-dimensional (2-D) sheets, whereas complex 3 has three-dimensional (3-D) frameworks and complex 4 has one-dimensional (1-D) tubular chains. The crystal-to-crystal transformation was observed in 1–3 upon removal of water molecules, which accompanied the changes in structures and ligand bridging modes. Furthermore, the electrochemical properties of complexes 3 and 4 have been studied to evaluate these compounds as electrode materials in lithium ion batteries with the discharge capacities of 120 and 257 mAhg−1 in the first thirty cycles, respectively.


Author(s):  
Ilya V. Bratkov ◽  
Tatyana F. Yudina ◽  
Aleksey G. Mel'nikov ◽  
Tatiana V. Ershova ◽  
Dmitriy A. Filimonov

The paper considers the problems of obtaining the new electrode materials used in the electric power sources. The electrode material was prepared by anodic electrophoretic deposition in an alkaline medium of graphite nanosized particles. Nanoscale carbon phase was obtained by graphite foil anodic polarization in sulfuric acid followed by ultrasonic dispersing of the obtained powder. Electrophoretic coatings were deposited on a stainless steel electrode at applied potentials in the range of 5-10 V. The dependence of the anodic current density and specific capacity of the deposited film is linear on the anode potential. The method of FT-IR spectroscopy to study the properties of the surface of the obtained film was used. It was shown that as a result of electrophoresis the sufficiently strong reduction of surface oxygen-containing groups represented mainly phenolic groups occurs. The optimal value of the potential for deposition of electrophoretic films - 5 V, for a given value after 5 min of electrophoresis formed film thickness is 430 nm with a minimum content of oxygen-containing surface groups. Electrochemical properties of the resulting films were determined with a cyclic voltammetry in an acidic medium. It was found that at value of the potential sweep rate of 20 mV/s the specific film capacity was 117 F/g.Forcitation:Bratkov I.V., Yudina T.F., Mel'nikov A.G., Ershova T.V., Filimonov D.A. Electrophoretic deposition of dispersed graphite and electrochemical properties of obtained films. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 3. P. 77-82.


Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2344
Author(s):  
Byung-Joo Kim ◽  
Kay-Hyeok An ◽  
Wang-Geun Shim ◽  
Young-Kwon Park ◽  
Jaegu Park ◽  
...  

Ag particles were precipitated on an activated carbon fiber (ACF) surface using a liquid phase plasma (LPP) method to prepare a Ag/ACF composite. The efficiency was examined by applying it as an adsorbent in the acetaldehyde adsorption experiment. Field-emission scanning electron microscopy and energy-dispersive X-ray spectrometry confirmed that Ag particles were distributed uniformly on an ACF surface. X-ray diffraction and X-ray photoelectron spectroscopy confirmed that metallic silver (Ag0) and silver oxide (Ag2O) precipitated simultaneously on the ACF surface. Although the precipitated Ag particles blocked the pores of the ACF, the specific surface area of the Ag/ACF composite material decreased, but the adsorption capacity of acetaldehyde was improved. The AA adsorption of ACF and Ag/ACF composites performed in this study was suitable for the Dose–Response model.


2018 ◽  
Vol 44 (15) ◽  
pp. 18420-18428 ◽  
Author(s):  
Zhaohui Han ◽  
Lei Xu ◽  
Chandrasekar Srinivasa Kannan ◽  
Jianhua Liu ◽  
Sivasankar Koppala ◽  
...  

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2195
Author(s):  
Kannadasan Thiagarajan ◽  
Dhandapani Balaji ◽  
Jagannathan Madhavan ◽  
Jayaraman Theerthagiri ◽  
Seung Jun Lee ◽  
...  

In the present study, the synthesis of CoWO4 (CWO)–Ni nanocomposites was conducted using a wet chemical method. The crystalline phases and morphologies of the Ni nanoparticles, CWO, and CWO–Ni composites were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDAX). The electrochemical properties of CWO and CWO–Ni composite electrode materials were assessed by cyclic voltammetry (CV), and galvanostatic charge–discharge (GCD) tests using KOH as a supporting electrolyte. Among the CWO–Ni composites containing different amounts of Ni1, Ni2, and Ni3, CWO–Ni3 exhibited the highest specific capacitance of 271 F g−1 at 1 A g−1, which was greater than that of bare CWO (128 F g−1). Moreover, the CWO–Ni3 composite electrode material displayed excellent reversible cyclic stability and maintained 86.4% of its initial capacitance after 1500 discharge cycles. The results obtained herein demonstrate that the prepared CWO–Ni3 nanocomposite is a promising electrode candidate for supercapacitor applications.


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