Nanocomposites of MnS anchored on graphene, nitrogen-doped graphene and boron-doped graphene have been prepared by a simple wet chemical process.

Nirmala Grace A

Centre for Nanotechnology Research

Vellore Campus

Ramachandran R

Saranya M

Grace A.N

Wang F.

Fulltext

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

RSC Advances

With high power density and promising possibilities for high energy density, the electrochemical capacitor has become an indispensable energy storage device to satisfy the future energy demands. Here in, we report on synthesis of graphene nanosheets (GNS) supported manganese sulfide (MnS) hybrid (GNS-MnS) nanocomposite by a simple, facile hydrothermal process. The resultant GNS-MnS hybrid nanocomposite with robust electronic amalgamation facilitates swift transfer of both ions and electrons across the interface between electrode surface and electrolyte ions than pristine MnS. Benefiting from the better conduction along with improved active sites of the MnS in GNS-MnS hybrid nanocomposite, a high ratio surface/near-surface reactions is dominated by high specific capacity even at high current rate. As such, the GNS-MnS hybrid nanocomposite exhibited a maximum specific capacitance of 792 F g −1 at 2 A g −1 along with better retention rate of 58% at 15 A g −1 , is significantly higher than that of pristine MnS (423 F g −1 at 2 A g −1 and 37% retention at 15 A g −1 ). In addition, the fabricated symmetric GNS-MnS hybrid nanocomposite cell delivered a high energy density of 25 W h kg −1 and power density of 7160 W kg −1 . Moreover, specific capacitance of 91.1% is retained after 15000 th cycles with columbic efficiency of ∼100% at 20 A g −1 . The remarkable electrochemical performance of GNS-MnS hybrid nanocomposite electrode demonstrated its potential as a key material for developing high energy supercapacitors. © 2019 Elsevier B.V.

Materials Chemistry and Physics

Synthesis of GNS-MnS hybrid nanocomposite for enhanced electrochemical energy storage applications

Spherical-like ball-by-ball architecture of Ni-Co-Zn-S was obtained through one pot simple and facile hydrothermal method without any surfactant. The as synthesized crystalline powder was characterized by using various tools like powder X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Furthermore, the electrochemical performance studies were carried out from cyclic-voltammetry (CV), galvanostatic charge–discharge (CD) and electrochemical impedance spectroscopy (EIS), within 3.5 M KOH. The consistent increment of clear redox peaks were obtained from CV characteristics due to synergic activities of Ni, Co and Zn. In addition, the presence of Zn ions into Ni and Co has increased its electronic conductivity; therefore, we could observe the superior performance. Thus, Ni-Co-Zn-S exhibited a maximum specific capacitance of 825, 680, 582, 512, 460, 432, 392 and 328 Fg−1 at 1, 2, 3, 4, 5, 6, 7 and 10 Ag−1 within 3.5 M KOH electrolyte. The obtained results are suggesting the excellent electrochemical activities with affordable rate of Ni-Co-Zn-S which is suitable electrode for device applications. Thus, our results may pave the way for the fabrication of advanced high energy storage device through a low-cost preparation to attain the extraordinary limit in energy device industry. © 2017 The Electrochemical Society. All rights reserved.

Journal of The Electrochemical Society

Spherical-Like Ball-by-Ball Architecture of Ni-Co-Zn-S Electrodes for Electrochemical Energy Storage Application in Supercapacitors

Zinc sulfide decorated graphene nanocomposites are synthesized by a facile solvothermal approach and the prepared composites are analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), High Resolution Transmission electron microscopy (HRTEM), Fourier transform infrared (FTIR), Ultraviolet visible spectroscopy (UV), Photoluminescence spectroscopy (PL) and Raman spectrum. Results show the effective reduction of graphene oxide (GO) to graphene and decoration of ZnS nanoparticles on graphene sheets. Towards supercapacitor applications, the electrochemical measurements of different electrodes are performed in 6 M KOH electrolyte. A series of composites with different loadings of graphene is synthesized and tested for its electrochemical properties. The specific capacitance of the electrodes are evaluated from cyclic voltammetry (CV) studies and a maximum specific capacitance of 197.1 F/g is achieved in ZnS/G-60 electrode (60 indicates the weight ratio of GO) at scan rate of 5 mV s-1. A capacitance retention of about 94.1% is observed even after 1000 cycles for ZnS/G-60 electrode, suggesting the long time cyclic stability of the composite electrode. Galvanostatic charge-discharge curves show the highly reversible process of ZnS/G-60 electrode. Electrochemical Impedance Spectrum (EIS) shows a high conductivity of composite electrode suggesting that the composites are good candidates for energy storage. © 2015 Elsevier Ltd.

Electrochimica Acta

Solvothermal synthesis of Zinc sulfide decorated Graphene (ZnS/G) nanocomposites for novel Supercapacitor electrodes

A simple chemical route was adopted for the preparation of graphene by chemical reduction route using sodium borohydride (NaBH4) as a reducing agent. A systematic study was done to show the effect of NaBH4 on the reduction and the obtained graphene samples were characterized using X-ray diffraction, Fourier transform spectroscopy, Raman spectroscopy, Atomic force microcopy and High resolution transmission electron microscopy. Better reduction of GO was observed at GO and NaBH4 ratio of 1:10 (denoted as SR1:10). Further, the investigation was emphasized to show the effect of the above GO to reductant ratio on its charge storage properties. Electrochemical measurements were carried out in 6M KOH electrolyte and the results show that the capacitance performance was increased in the order of GO&lt;SR1:8&lt;SR1:4&lt;SR1:12&lt;SR1:10. A high specific capacitance of 284.3F/g was observed for SR1:10 electrode at 5mV/s scan rate could be due to better electrical conductivity of sample. The ratio of GO and NaBH4 was optimized to 1:10 for high degree reduction of graphene, which has higher capacitance towards supercapacitor applications. © 2015 Elsevier Ltd.

Applied Energy

Effect of reducing agent on graphene synthesis and its influence on charge storage towards supercapacitor applications

Co9S8/graphene nanocomposites (Co9S8/G) at various concentrations of graphene and Co9S8 were prepared and tested for its electrochemical behaviour for supercapacitors.

RSC Adv.

Co9S8 nanoflakes on graphene (Co9S8/G) nanocomposites for high performance supercapacitors

Graphene platelets were synthesized from graphene oxide by chemical and electrochemical route. Under the chemical method, sodium borohydride and hydrazine chloride were used as reductants to produce graphene. In this paper, a novel and cost effective electrochemical method, which can simplify the process of reduction on a larger scale, is demonstrated. The electrochemical method proposed in this paper produces graphene in powder form with good yield. The atomic force microscopic images confirmed that the graphene samples prepared by all the routes have multilayers of graphene. The electrochemical process provided a new route to make relatively larger area graphene sheets, which will have interest for further patterning applications. Attempt was made to quantify the quantum of reduction using cyclic voltammetry and choronopotentiometry techniques on reduced graphene samples. As a measure in reading the specific capacitance values, a maximum specific capacitance value of 265.3 F/g was obtained in sodium borohydride reduced graphene oxide. © 2013 Elsevier Ltd. All rights reserved.

Materials Research Bulletin

Synthesis of graphene platelets by chemical and electrochemical route

Synthesis and properties of morphology controllable copper sulphide nanosheets for supercapacitor application

MnS nanocomposites based on doped graphene: simple synthesis by a wet chemical route and improved electrochemical properties as an electrode material for supercapacitors

Journal	Data powered by TypesetRSC Advances
Publisher	Data powered by TypesetRoyal Society of Chemistry (RSC)
ISSN	20462069
Open Access	Yes