Petal-like MoS2 nanostructures with metallic 1 T phase for high performance supercapacitors

Rajneesh Kumar Mishra,SHANMUGAMMANIVANNAN,김규원,권혁인,진성훈 한국물리학회 2018 Current Applied Physics Vol.18 No.3

Herein, we report the metallic 1 T phase MoS2 petal-like nanostructures (MP-LNs), synthesized by the solvothermal method, for applications in supercapacitor electrodes. X-ray photoelectron spectroscopy (XPS) verified the composition and distribution of Mo and S, illustrating that the 1 T metallic phase is predominant in the MP-LNs. Electrochemical analyses were performed to explore the supercapacitor applications of the MP-LN material, demonstrating a superior cyclic voltammetry (CV), high specific capacitance, good stability. MP-LN-based supercapacitors (MP-LNS) show high specific capacitances of 811 F/g and 400 F/g at current densities of 0.1 A/g and 10 A/g, respectively. The long-term cycling stability was also studied to investigate the reproducible nature of MP-LNS and was found to display excellent specific capacitance retention of 49.3% (at 0.1 A/g) and 82.7% (at 10 A/g) after 1000 charge-discharge cycles, which indicates good reversibility of the galvanostatic charge-discharge (GCD) of the electrode material. These findings highlight the potential use of MP-LNs in supercapacitors.

Novel two-dimensional In₂O₃ nanodiscs for high-rate performance of solid-state symmetric supercapacitors

Mishra, Rajneesh Kumar,Ryu, Jae Hyeon,Kwon, Hyuck-In,Jin, Sung Hun Elsevier 2018 Materials letters Vol.218 No.-

<P><B>Abstract</B></P> <P>In this study, we report a two-dimensional In<SUB>2</SUB>O<SUB>3</SUB> nanodiscs for solid-state symmetric supercapacitors (SSCs) synthesized by one-step hydrothermal method. It exhibits high specific capacitance of 622 F g<SUP>−1</SUP> at 3 A g<SUP>−1</SUP> and 412 F g<SUP>−1</SUP> at 7 A g<SUP>−1</SUP> based on individual electrodes. Further, the SSCs demonstrate a wide potential window of 1.0 V, excellent specific capacitance of 89.7 F g<SUP>−1</SUP> at a current density of 1 A g<SUP>−1</SUP>, a high energy density of 12.5 W h kg<SUP>−1</SUP> at a power density of 500 W kg<SUP>−1</SUP>, and an outstanding stability with ∼97% rate retention after 10,000 cycles. The superior performances of the SSCs with 2D In<SUB>2</SUB>O<SUB>3</SUB> nanodiscs material suggest their potential opportunity for future electronic applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel two-dimensional (2D) In<SUB>2</SUB>O<SUB>3</SUB> nanodisc for a high rate performance in SSCs. </LI> <LI> Ion diffusion control through geometrical shape modification in supercapacitors (SSCs) </LI> <LI> An outstanding stability with ∼97% specific capacitance retention after 10,000 cycles. </LI> </UL> </P>

Vertical-slate-like MoS2 nanostructures on 3D-Ni-foam for binder-free, lowcost, and scalable solid-state symmetric supercapacitors

Rajneesh Kumar Mishra,Ajay Kumar Kushwaha,김승엽,서승기,진성훈 한국물리학회 2019 Current Applied Physics Vol.19 No.1

Here, we report binder-free vertical-slate-like MoS2 nanostructures on 3D-Ni-Foam (VSL-MoS2@3D-Ni foam) for low-cost high-performance solid-state symmetric supercapacitors (SSCs). The cost-effective, ecofriendly and scalable solvothermal method and its direct incorporation of VSL-MoS2@3D-Ni-foam yield SSCs with excellent electrochemical properties with a wide potential window of 1.0 V. Furthermore, high specific capacitance of 34.1 F g−1 at a current density of 1.3 A g−1, an energy density of 4.7Wh kg−1 at a high-power density of 650Wkg−1, and excellent stability with ∼82.5% capacitance retention after 10,000 cycles were demonstrated even for SSCs with a binder free MoS2 electrodes on 3D-Ni-foam. These excellent features of the SSCs with VSLMoS2@ 3D-Ni-foam substantiate their potential opportunity for future energy applications.

One-step solvothermal synthesis of carnation flower-like SnS₂ as superior electrodes for supercapacitor applications

Mishra, Rajneesh Kumar,Baek, Geun Woo,Kim, Kyuwon,Kwon, Hyuck-In,Jin, Sung Hun Elsevier 2017 APPLIED SURFACE SCIENCE - Vol.425 No.-

<P><B>Abstract</B></P> <P>We report the synthesis of carnation flower-like SnS<SUB>2</SUB> (CF-SnS<SUB>2</SUB>) via a one-step solvothermal method for potential application as supercapacitor electrodes in energy storage devices. The structural and morphological properties of CF-SnS<SUB>2</SUB> were characterized by X-ray diffraction, Raman analysis, and field-emission scanning and transmission electron microscopies. X-ray photoelectron spectroscopy and scanning tunneling electron microscopy with color mapping verified the distribution of Sn and S, and depicted the successful formation of SnS<SUB>2</SUB>. Electrochemical studies were performed to explore the supercapacitive nature of CF-SnS<SUB>2</SUB>. Supercapacitors with CF-SnS<SUB>2</SUB> electrodes delivered excellent cyclic voltammetry performances, superior gravimetric specific capacitances, and high power densities. The evaluated specific capacitance and power density reached ∼524.5F/g and 12.3W/kg, respectively, at a current density of 0.08A/g, and ∼215.9F/g and 61.4W/kg, respectively, at a current density of 0.38A/g. These values are at least two times higher than those previously reported. The long-term cyclic stability was also tested to demonstrate the endurance of the CF-SnS<SUB>2</SUB>-based supercapacitor, with a 66% rate retention and galvanostatic charge/discharge reversibility. These electrochemical findings indicate that CF-SnS<SUB>2</SUB> is a promising candidate for electrode materials in supercapacitor applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The first synthesis of carnation flower-like SnS<SUB>2</SUB> (CF-SnS<SUB>2</SUB>) by one-step solvothermal method and CF-SnS<SUB>2</SUB> growth mechanism studies were reported. </LI> <LI> CF-SnS<SUB>2</SUB> morphology and the hexagonal crystallographic phase with peak (001) plane was verified by various peak analyses including XRD and Raman, enlightening that the novel surface chemistry enhance the performance of electrodes in super capacitors. </LI> <LI> Pore accessibility of electrolyte ions in the CF-SnS<SUB>2</SUB> depending on frequency was systematically studied by using electrochemical impedance spectroscopy, substantiating that the good capacitive nature and excellent cyclic stability of the CF- SnS<SUB>2</SUB>-based supercapacitor were strongly influenced by the ion accessibility in this system. </LI> </UL> </P>

Vertical-slate-like MoS₂ nanostructures on 3D-Ni-foam for binder-free, low-cost, and scalable solid-state symmetric supercapacitors

Mishra, Rajneesh Kumar,Kushwaha, Ajay Kumar,Kim, Seungyeob,Seo, Seung Gi,Jin, Sung Hun Elsevier 2019 CURRENT APPLIED PHYSICS Vol.19 No.1

<P><B>Abstract</B></P> <P>Here, we report binder-free vertical-slate-like MoS<SUB>2</SUB> nanostructures on 3D-Ni-Foam (VSL-MoS<SUB>2</SUB>@3D-Ni foam) for low-cost high-performance solid-state symmetric supercapacitors (SSCs). The cost-effective, ecofriendly and scalable solvothermal method and its direct incorporation of VSL-MoS<SUB>2</SUB>@3D-Ni-foam yield SSCs with excellent electrochemical properties with a wide potential window of 1.0 V. Furthermore, high specific capacitance of 34.1 F g<SUP>−1</SUP> at a current density of 1.3 A g<SUP>−1</SUP>, an energy density of 4.7 W h kg<SUP>−1</SUP> at a high-power density of 650 W kg<SUP>−1</SUP>, and excellent stability with ∼82.5% capacitance retention after 10,000 cycles were demonstrated even for SSCs with a binder free MoS<SUB>2</SUB> electrodes on 3D-Ni-foam. These excellent features of the SSCs with VSL-MoS<SUB>2</SUB>@3D-Ni-foam substantiate their potential opportunity for future energy applications.</P>

A new strategy for integrating semiconducting SWCNTs into pseudo-cubic In₂O₃ heterostructures for solid-state symmetric supercapacitors with a superior stability and specific-capacitance

Mishra, Rajneesh Kumar,Ryu, Jae Hyeon,Kwon, Hyuck-In,Jin, Sung Hun The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.31

<P>Herein, we report a rapid one-step hydrothermal synthesis of semiconducting single-walled carbon nanotubes/pseudo-cubic In2O3 heterostructures (s-S/IHs) and successfully demonstrate LED lighting by using symmetric solid-state supercapacitors (SSCs). This is a simple, scalable, proficient and <I>in situ</I> synthesis method to harvest materials that can be engaged as cutting-edge electrode materials for high-energy SSCs. The cost effective and environment-friendly s-S/IH conveys excellent electrochemical properties with a high specific capacitance (641.1 F g<SUP>−1</SUP> at a current density of 1.8 A g<SUP>−1</SUP>) and tremendous rate capabilities with an excellent capacitance (335.1 F g<SUP>−1</SUP> at a current density of 3.8 A g<SUP>−1</SUP>). The SSC devices with a maximum potential window of 1.2 V are fabricated by using two similar s-S/IH electrodes in order to justify the outstanding performance for real-life energy storage devices. Notably, the SSC devices offered a high specific capacitance (139.5 F g<SUP>−1</SUP> at 2 A g<SUP>−1</SUP>), a high energy density (6.9 W h kg<SUP>−1</SUP> at 234.3 W kg<SUP>−1</SUP>), an ultra-high power density (789.3 W kg<SUP>−1</SUP> at 4.6 W h kg<SUP>−1</SUP>), and a remarkable cycling stability (91.8% specific capacitance retention rate after 5000 cycles). These extraordinary findings illustrate an insight into designing a nanocube In2O3 lattice deformed by very small concentration of semiconducting single-walled carbon nanotubes that are economically affordable and environmentally harmonious for the fabrication and demonstration of high performance SSC devices.</P>

Petal-like MoS₂ nanostructures with metallic 1 T phase for high performance supercapacitors

Mishra, Rajneesh Kumar,Manivannan, Shanmugam,Kim, Kyuwon,Kwon, Hyuck-In,Jin, Sung Hun ELSEVIER 2018 CURRENT APPLIED PHYSICS Vol.18 No.3

<P>Herein, we report the metallic 1 T phase MoS2 petal-like nanostructures (MP-LNs), synthesized by the solvothermal method, for applications in supercapacitor electrodes. X-ray photoelectron spectroscopy (XPS) verified the composition and distribution of Mo and S, illustrating that the 1 T metallic phase is predominant in the MP-LNs. Electrochemical analyses were performed to explore the supercapacitor applications of the MP-LN material, demonstrating a superior cyclic voltammetry (CV), high specific capacitance, good stability. MP-LN-based supercapacitors (MP-LNS) show high specific capacitances of 811 F/g and 400 F/g at current densities of 0.1 A/g and 10 A/g, respectively. The long-term cycling stability was also studied to investigate the reproducible nature of MP-LNS and was found to display excellent specific capacitance retention of 49.3% (at 0.1 A/g) and 82.7% (at 10 A/g) after 1000 charge-discharge cycles, which indicates good reversibility of the galvanostatic charge-discharge (GCD) of the electrode material. These findings highlight the potential use of MP-LNs in supercapacitors. (C) 2017 Elsevier B.V. All rights reserved.</P>

Effect of Indium Doping and Annealing on Photoconducting Property of Wurtzite Type CdS

Vineet Kumar Singh,Pratima Chauhan,Sheo Kumar Mishra,Rajneesh K Srivastava 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.3

In this paper we observed the effect of doping and annealing on the dark current and anomalous photoconducting behavior of hexagonal wurtzite CdS, synthesized by solid state reaction method. Undoped CdS sample shows higher anomalous behavior in photoconductivity as well as contains larger dark current of 19 nA. With the doping of Indium in CdS, dark current decreases from 19 nA to 1 nA but the anomalous behavior is not completely removed. While, after annealing at 150°C for four hour, indium doped CdS sample shows good switching property with rise and decay time of 360 ± 10 & 322 ± 6 seconds respectively. The anomalous photoconducting behavior is completely removed from annealed sample. X-ray diffraction patterns confirm the existence of hexagonal wurtzite phase of indium doped and undoped CdS samples while energy dispersion X-ray spectrum exhibits the elemental presence of cadmium, indium & sulfur in the indium doped sample. UV-Visible absorption spectra show the blue shift in absorption edge on indium doping from 475 nm to 425 nm in comparison to undoped sample. Photoluminescence spectra confirm the indium doping and reveal that annealed CdS sample has lesser defects among other samples due to which annealed sample has best switching performance.

Anchoring energy of nematic liquid crystals on zinc oxide film

Ryu Dae Geon,Choi Gyu Jin,Mishra Rajneesh Kumar,Gwag Jin Seog 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.78 No.4

The potential of a ZnO transparent electrode as a liquid crystal (LC) alignment layer was assessed by measuring the surface LC anchoring strength. This can be determined by observing the direction of the William domain, which is one of the many patterns generated in liquid crystal electroconvection. The surface of the ZnO layer is modulated by a conventional rubbing method with a rubbing machine and ion beam method to align the LCs and thus, allow the ZnO layer to act as an LC alignment layer. To increase the surface anchoring energy of the ZnO film further, a linear ion-beam irradiation was carried out after rubbing the ZnO layer for the synergistic effect of the alignment techniques, after which the azimuthal surface anchoring energy of the ZnO layer was about 2.23 × 10–5 J/m2, which is comparable to the conventional alignment layer, polyimide, used at currently LC displays.

Does Timing of Completion Radical Cholecystectomy Determine the Survival Outcome in Incidental Carcinoma Gallbladder - A Single Center Retrospective Analysis

( Rahul R. ),( Kulbhushan Haldeniya ),( Ashish Singh ),( Prabhakar Mishra ),( Rajneesh Kumar Singh ),( Anu Behari ),( Vinay Kumar Kapoor ),( Rajan Saxena ) 대한간학회 2021 춘·추계 학술대회 (KASL) Vol.2021 No.1