Papers by vaibhav lokhande
Rational La-doped hematite as an anode and hydrous cobalt phosphate as a battery-type electrode for a hybrid supercapacitor
Dalton Transactions
In recent years, modern appliances require high energy density with a burst power supply.
Lanthanum sulfide-manganese sulfide/graphene oxide (La2S3-MnS/GO) composite thin film as an electrocatalyst for oxygen evolution reactions
Journal of Solid State Electrochemistry
In this study, the lanthanum sulfide-manganese sulfide (La2S3-MnS) nanosheet composite films with... more In this study, the lanthanum sulfide-manganese sulfide (La2S3-MnS) nanosheet composite films with different thicknesses were grown on graphene oxide (GO) (LMS/GO) coated stainless steel substrate using binder-free successive ionic layer adsorption and reaction (SILAR) method, for the first time. The formation of crystal structure and chemical states was identified using X-ray diffraction analysis and X-ray photoelectron spectroscopy, respectively. The nitrogen sorption analysis showed the micro-/mesoporous structure of La2S3-MnS-90/GO thin film exhibiting a specific surface area of 170 m2 g-1 and hydrophilic nature. The scanning electron microscopic image showed microstructure with porous ultrathin interconnected nanosheets. Surface texture was examined using transmission electron microscopy. The resulting La2S3-MnS-90/GO thin film electrocatalyst showed oxygen evolution reaction (OER) overpotential as low at 263 mV to reach 10 mA cm-2 current density with Tafel slope of 48 mV dec-1 for in 1 M KOH solution and stability over 50 h. Consequently, it could be considered one of the alternate sulfide-based catalysts for highly efficient OER evolution.
Binder‐Free Synthesis of Mesoporous Nickel Tungstate for Aqueous Asymmetric Supercapacitor Applications: Effect of Film Thickness
Energy Technology
Electrochromism in Hf-doped WO3
Journal of Solid State Electrochemistry
Journal of Solid State Electrochemistry, 2020
A straightforward process for synthesis of hybrid porous electrode material composed of reduced g... more A straightforward process for synthesis of hybrid porous electrode material composed of reduced graphene oxide (rGO) and copper sulfide (CuS) with layered structure on the stainless steel substrate is developed. As-synthesized hybrid electrode shows hexagonal crystal structure of CuS with 77 m 2 gm −1 specific surface area and 22 nm average pore size. The specific capacitance obtained with rGO-CuS5 hybrid electrode is 1201 F g −1 at the sweep rate of 5 mV s −1 in 1 M LiClO 4 aqueous electrolyte. The majority of charge stored by diffusion-controlled process indicates benefits of layered structures for solid-state energy storage. The rGO-CuS5-based hybrid symmetric supercapacitor delivers a specific capacitance (C s) as high as 109 F g −1 at a sweep rate of 5 mV s −1 with polyvinyl alcohol (PVA)-LiClO 4 gel electrolyte. Also, the specific energy of 44 Wh kg −1 and specific power of 1.4 kW kg −1 with 87% stability after 6000 cycles at an applied current of 5 mA are obtained. The simple process of synthesis of layered hybrid electrode material for flexible supercapacitor promises its use in smart textile and wearable electronic devices.
Journal of Physics and Chemistry of Solids, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Applied Physics A, 2020
In the field of energy conversion and storage, the cost-effective and highly active oxygen evolut... more In the field of energy conversion and storage, the cost-effective and highly active oxygen evolution reaction (OER) catalysts are in much demand. Herein, morphology dependant OER activity of Co 3 S 4 thin film electrodes fabricated using simple and cost effective successive ionic layer adsorption and reaction (SILAR) method is demonstrated for the first time. The morphology of Co 3 S 4 has been influenced by varying number of deposition cycles. The effect of change in morphology on the electrocatalytic properties of Co 3 S 4 thin film electrode is studied. The OER performance of Co 3 S 4 thin film is related to the morphology. The OER activity with an overpotential of 275 mV @10 mA cm −2 and Tafel slope of 53 mV dec −1 in 1 M KOH electrolyte is due to increased electrochemical active surface area, super-hydrophilic nature, and low electron transfer resistance of Co 3 S 4 thin film electrode.
Electrochemical Energy Technology, 2017
To enhance the energy density and power performance of supercapacitors, the rational design and s... more To enhance the energy density and power performance of supercapacitors, the rational design and synthesis of active electrode materials with hierarchical mesoporous structure is highly desired. In the present work, fabrication of high-performance hierarchical mesoporous WO
Effect of Acids on Synthesis of WO3 and their Application in Supercapacitor
Defect and Diffusion Forum, 2019
In this study, the characteristics of WO3 prepared with acidic solution were analyzed. The acidic... more In this study, the characteristics of WO3 prepared with acidic solution were analyzed. The acidic solution was prepared by using hydrochloric acid and sulfuric acid as the solutions to be added during the hydrothermal synthesis process. SEM, XRD and electrochemical characteristics tests were performed based on the prepared samples. Samples prepared in hydrochloric acid (W1) solution can identify platelet crystals and nanospheres, and samples made from sulfuric acid (W2) solutions can identify nanospheres and nanocubes. From the XRD data, it was confirmed that all of the diffraction peaks had a hexagonal phase. Electrochemical properties showed good rate capability of W1 samples but low capacitance and W2 samples showed relatively high capacitances.
Electrochimica Acta, 2019
New design of all-solid state asymmetric flexible supercapacitor with high energy storage and lon... more New design of all-solid state asymmetric flexible supercapacitor with high energy storage and long term cycling stability using m-CuO/FSS and h-CuS/FSS electrodes, Electrochimica Acta (2019), doi:
New Physics: Sae Mulli, 2019
In this study, the synthesis of WO3 using different acids was carried out to test its electrochem... more In this study, the synthesis of WO3 using different acids was carried out to test its electrochemical performance and applicability in electrochemical charge storage devices like supercapacitors. Hydrochloric acid (W1), sulfuric acid (W2) and nitric acid (W3) were used to synthesize WO3, which was deposited on a carbon cloth substrate via a hydrothermal route. X-ray diffraction (XRD) characterization confirmed the formation of hexagonal WO3 in all three samples. Scanning electron microscopy (SEM) was performed to analyze the morphology, size and shape of the deposited material, and different nano structures, such as nano spheres, nano rods and hexagonal platelets, were observed, which confirms the effect of different acids on the morphology, shape and size of the particle. Electrochemical characterizations using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) tests suggest that the samples exhibit charge-storage capability and can be utilized as active materials in energy storage devices. Sample W2 exhibits highest specific capacitance of 778 Fg −1 at 5 mVs −1 scan rate while W1 showed the lowest specific capacitance (500 Fg −1 at 5 mVs −1) of all three samples. The effect of acid on WO3 parameters and consequently its electrochemical performance has been discussed further.
Results in Physics, 2019
Tungsten oxide is a versatile material with different applications. It has many polymorphs with v... more Tungsten oxide is a versatile material with different applications. It has many polymorphs with varying performance in energy storage application. We report simple and facile way to synthesize four phases of tungsten oxide from same precursor materials only by changing the pH and temperature values. Monoclinic, hexagonal, orthorhombic and tetragonal phase obtained, were analyzed and tested for supercapacitor application. The electrochemical analysis of four phases indicates that the hexagonal phase is best-suited electrode material for supercapacitor. The hexagonal phase exhibits higher specific capacitance (377.5 Fg −1 at 2 mV s −1), higher surface capacitive contribution (75%), better stability and rate capability of all four phases.
International Journal of Hydrogen Energy, 2018
In present study, new strategy is employed to build composite nanostructure and asymmetric config... more In present study, new strategy is employed to build composite nanostructure and asymmetric configuration to enhance the capacitive performance of supercapacitor device. The WO 3-MnO 2 composite with mesoporous structure is prepared by single-step hydrothermal method and used to gain superior electrochemical performance in asymmetric configuration. A binder-free and additive-less WO 3-MnO 2 composite electrode exhibits high specific capacitance of 609 F g À1 at a scan rate of 5 mV s À1. The flexible asymmetric supercapacitor device with WO 3-MnO 2 as a positive electrode and WO 3 as a negative electrode demonstrates stable operating potential window of 1.4 V with specific capacitance of 103 F g À1 at a scan rate of 5 mV s À1 and energy density of 24.13 Wh kg À1 at power density of 915 W kg À1. Furthermore, WO 3-MnO 2 //WO 3 device exhibits good cycle life with capacity retention of 95% after 2500 cycles and excellent mechanical flexibility. These results reveal the potential of WO 3-MnO 2 composite electrode for fabrication of highperformance supercapacitors.
Electrochimica Acta, 2018
The obtained porous microstructure of the CTS thin film electrode using SILAR method and its elec... more The obtained porous microstructure of the CTS thin film electrode using SILAR method and its electrochemical characterization in solid-state symmetric configuration. The CV and GCD curves are accomplished in the potential window range of 0-1.2 V. The device exhibited 89.9 % stability retention after 1000 CV cycles.
Rate controlled metal assisted chemical etching to fabricate vertical and uniform Si nanowires
Advanced Fabrication Technologies for Micro/Nano Optics and Photonics IX, 2016
Mac(metal assisted chemical) etching is a simple, low-cost and anisotropic etching method to make... more Mac(metal assisted chemical) etching is a simple, low-cost and anisotropic etching method to make Si NWs (silicon nanowires). In this method, smaller surface area is damaged compared to dry etching process, either. Mac etching uses a combination of an oxide removal acid (e.g. HF), an oxidant (e.g. H2O2) with a noble metal (e.g. Au, Ag, Pt, etc.) as the catalyst. Typically, the Si beneath the noble metal is etched faster than the Si without noble metal coverage by electron transfer mechanism at the noble metal /solution and the noble metal/Si interface. While Mac etching to build Si NWs, unwanted etching occurs in the bulk silicon layer resulting from excess hole diffusion caused by the increase in hole concentration at the nearby metal layers. In this study, we explored the ratio of oxidant to oxide removal acid in the Mac etching solution that is most effective in etching the Si underneath the noble metal layer suppressing the unwanted etching. At the optimized ratio, Si NWs were fabricated at a faster rate with good uniformity.
Amperometric CO2 gas sensor based on interconnected web-like nanoparticles of La2O3 synthesized by ultrasonic spray pyrolysis
Microchimica Acta, 2017
AbstractThin films of La2O3 were deposited onto glass substrates by ultrasonic spray pyrolysis. T... more AbstractThin films of La2O3 were deposited onto glass substrates by ultrasonic spray pyrolysis. Their structural and morphological properties were characterized by X-ray diffraction, Fourier transform Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photo-electron spectroscopy, Brunauer-Emmett-Teller and optical absorption techniques. The sensor displays superior CO2 gas sensing performance at a low operating temperature of 498 K. The signal change on exposure to 300 ppm of CO2 is about 75%, and the signal only drops to 91% after 30 days of operation. Graphical abstractSchematic diagram of the CO2 gas sensing mechanism of an interconnected web-like La2O3 nanostructure in presence of 300 ppm of CO2 gas and at an operating temperature of 498 K.
Fabrication of high performance flexible all-solid-state asymmetric supercapacitors with a three dimensional disc-like WO3/stainless steel electrode
RSC Advances, 2016
The schematic of steps involved in fabrication of flexible MnO2//WO3 ASCs device.
Enhanced electrochemical performance of monoclinic WO3 thin film with redox additive aqueous electrolyte
Journal of colloid and interface science, Jan 12, 2016
To achieve the highest electrochemical performance for supercapacitor, it is very essential to fi... more To achieve the highest electrochemical performance for supercapacitor, it is very essential to find out a suitable pair of an active electrode material and an electrolyte. In the present work, a simple approach is employed to enhance the supercapacitor performance of WO3 thin film. The WO3 thin film is prepared by a simple and cost effective chemical bath deposition method and its electrochemical performance is tested in conventional (H2SO4) and redox additive [H2SO4+hydroquinone (HQ)] electrolytes. Two-fold increment in electrochemical performance for WO3 thin film is observed in redox additive aqueous electrolyte compared to conventional electrolyte. WO3 thin film showed maximum specific capacitance of 725Fg(-1), energy density of 25.18Whkg(-1) at current density of 7mAcm(-2) with better cycling stability in redox electrolyte. This strategy provides the versatile way for designing the high performance energy storage devices.
Electrochemical impedance analysis of spray deposited CZTS thin film: Effect of Se introduction
Optical Materials, 2016
Abstract The present work deals with electrochemical impedance analysis of spray deposited Cu2ZnS... more Abstract The present work deals with electrochemical impedance analysis of spray deposited Cu2ZnSnS4 (CZTS) thin films grown on fluorine doped tin oxide (FTO) substrates and effect of post Se introduction. The CZTS thin films are characterized using X-ray diffraction (XRD), X-Ray photo spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and UV–Vis spectroscopy techniques. The electrochemical measurements are carried out using impedance analysis spectroscopy. The strong peak in XRD pattern along (112) plane confirms the Kestrite crystal structure of CZTS film. The FE-SEM analysis reveals that nanoflakes contain crack-free surface microstructure changes with post Se introucation. The optical study reveals that absorption increases with Se dipping time and observed lower band gap of 1.31 eV. Introduction of Se in CZTS film results an improvement in the grain size and surface morphology which leads to increased electrical conductivity of CZTS film.
Journal of Materials Science: Materials in Electronics, 2015
Hexagonal microrods containing MoO 3 thin films are synthesized by simple, low cost and scalable ... more Hexagonal microrods containing MoO 3 thin films are synthesized by simple, low cost and scalable chemical bath deposition approach with acidification of ammonium molybdate ([NH 4 ]6Mo 7 O 24 Á4H 2 O). The structural and morphological analyses are carried out through X-ray diffraction and field emission scanning electron microscopy (FE-SEM) respectively. Hexagonal microrods of width *5 lm and length of *20-50 lm are manifested in FE-SEM analysis. Supercapacitive tests of electrode are performed with cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) techniques in 1 M Na 2 SO 4 electrolyte. The highest specific capacitance of 194 Fg-1 is obtained from CV study. The energy and power densities of 7.33 Wh kg-1 and 1200 W kg-1 , respectively are obtained from GCD study. An electrochemical impedance spectroscopic study is also carried out.
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Papers by vaibhav lokhande