Sanjit Saha - Academia.edu (original) (raw)

Papers by Sanjit Saha

Journal of Power Sources, Feb 1, 2017

Layer-by-layer assembly (LbL) of MnO 2 and reduced graphene oxide (RGO) is prepared. The LbL acts... more Layer-by-layer assembly (LbL) of MnO 2 and reduced graphene oxide (RGO) is prepared. The LbL acts as single material with hybrid electrochemical properties. Uniform distribution of MnO 2 over RGO exhibits high specific capacitance. No organic binder is used to design the supercapacitor electrodes.

Materials Chemistry and Physics, 2017

Journal of energy storage, Jun 1, 2018

The typical physical and chemical properties lead the nanomaterials to breakthrough in the field ... more The typical physical and chemical properties lead the nanomaterials to breakthrough in the field of energy storage especially, supercapacitor applications. The optimization of electrical conductivity, structural flexibility, band gap and charge carrier mobility are the key point to solve the issues in the electrochemical charge storage mechanism of supercapacitor. The semiconducting heterostructured nanomaterials are the best choice to store energy by near-surface ion adsorption along with additional contribution from fast reversible faradic reactions. The creation of active sites and defects in the grain boundary of the heterostructure materials results in multiple redox activity, superior ionic conductivity and short diffusion path. Therefore, sufficient researches enrooted to the doped and nano heterostructure electrode materials needs to be performed in order to exploit the high power and energy storage applications. This article reviews current trends in the synthesis of heterostructure electrode through hybridization of different electrochemical double layer capacitance (EDLC) and pseudocapacitive materials. This article also emphasize on the effect of doping on the electrode possessing both EDLC as well as the pseudocapacitance. In addition, the advantages of superlattice structure for the superior electrochemical properties are also discussed.

Journal of Industrial and Engineering Chemistry, Aug 1, 2017

Functionalization and electrodeposition of reduced graphene oxide/hexagonal boron nitride (rGO/h-... more Functionalization and electrodeposition of reduced graphene oxide/hexagonal boron nitride (rGO/h-BN) superlattice was carried out by a novel one-step electrochemical process. The sulfanilic acid azochromotrop (SAA) functionalized and electrodeposited nickel foam (SAA@rGO/h-BN@Ni) electrode showed high specific capacitance of ~1300 F g-1. An 3 asymmetric supercapacitor cell (ASC) using SAA@rGO/h-BN@Ni as positive and thermally reduced GO as negative electrode showed ~80% capacitance retention after 10,000 chargedischarge cycles. The ASC showed low relaxation time constant of ~ 0.47 ms along with high energy density (~95.3 W h kg-1) and power density (~7200 W kg-1) ensuring the utility of SAA@rGO/h-BN@Ni electrode for supercapacitor application.

Journal of energy storage, May 1, 2016

In-situ deposition of MnO 2 /NiO hetero structure on Ni-foam has been carried out through simple ... more In-situ deposition of MnO 2 /NiO hetero structure on Ni-foam has been carried out through simple onestep hydrothermal reaction. The in-situ deposited multi-metal oxide shows extraordinary electrocatalytic activity in hydrogen evolution reaction with a small Tafel slope of 38 mV per decade and very low onset potential of 0.17 V. An electrolyser has been fabricated with MnO 2 /NiO deposited Ni-foam which effectively achieves a current density of 24mAcmAˋ2atanappliedvoltageof24 mA cm À2 at an applied voltage of 24mAcmAˋ2atanappliedvoltageof1.57 V. Furthermore, the metal oxide deposited on Ni-foam is directly used as the supercapacitor electrode which shows good rate capability as positive electrode materials. An asymmetric capacitor (ASC) has been assembled by using the MnO 2 /NiO deposited Ni-foam as positive electrode and thermally reduced graphene oxide as negative electrode. The assembled ASC has a large specific capacitance of 218 F g À1 at a current density of 3 A g À1 and can deliver high energy and power density of 59.5 Wh kg À1 and 25,350 W kg À1 , respectively. The ASC shows very good electrochemical stability throughout 10,000 charge-discharge cycles along with the capability to work in the high frequency range.

ChemistrySelect, Jan 15, 2019

was grafted on to the 2D rGO/h-BN by electroprecipitation method. Nitrogen of h-BN moiety and oxy... more was grafted on to the 2D rGO/h-BN by electroprecipitation method. Nitrogen of h-BN moiety and oxygen functional groups of rGO played the role of negative active site to trap the metallic cations. Electrochemical charge storage mechanism was optimized by controlling the stoichiometry and defect contents of Fe 3 O 4 /NiO@rGO/h-BN. Stoichiometry of the electro-precipitated samples was tailored in presence of negative active sites of rGO/h-BN and applied D.C. bias of the electrochemical bath. In addition, the nucleation and growth of metal oxides were influenced by the stacking and vacancy defects of rGO/h-BN sheets. High specific capacitance (1328 F g À 1) of Fe 3 O 4 /NiO@rGO/h-BN was attributed to the synergistic effect of electrochemical double layer capacitance of rGO, chemi-adsorption of-OH ions on Lewis acid (boron of h-BN moiety) and redox capacitance of Fe 3 O 4 /NiO in alkaline medium. In addition, the presence of pyrrolic defect at the rGO/h-BN stacking region acted as the nucleation site and provided additional redox capacitance by shifting the Fermi level towards the valance band. An asymmetric supercapacitor (ASC) was constructed using Fe 3 O 4 /NiO@rGO/h-BN and thermally reduced GO as positive and negative electrode, respectively. ASC showed high energy (82 W h Kg À 1) and power density (5600 W Kg À 1) along with low relaxation time constant (2.2 ms) and high stability (79%) after 10,000 charge discharge cycles.

John Wiley & Sons, Inc. eBooks, Jun 13, 2014

ABSTRACT This chapter contains sections titled: Introduction Principles of Chemical Sensing by Co... more ABSTRACT This chapter contains sections titled: Introduction Principles of Chemical Sensing by Conducting Nanocomposite Materials Synthesis of Graphene and its Nanocomposites Characterization of Graphene and its Nanocomposites Chemical Sensing of Graphene and its Nanocomposites Conclusion and Future Aspects Acknowledgements

Physical Chemistry Chemical Physics, 2017

Non-covalent functionalized rGO showed superior plasmonic response and high donor density through... more Non-covalent functionalized rGO showed superior plasmonic response and high donor density through a large frequency range at the electrode–electrolyte interface.

Journal of Power Sources, 2017

Journal of materials chemistry. A, Materials for energy and sustainability, 2018

Materials Science and Engineering: B, 2014

ABSTRACT Green reduction of graphene oxide (GO) using drained water from soaked mung beans (Phase... more ABSTRACT Green reduction of graphene oxide (GO) using drained water from soaked mung beans (Phaseolus aureus L.) has been demonstrated. In comparison to the toxic and hazardous reducing chemicals, the drained water from soaked mung beans (P. aureus L.) is completely green reducing agent, the reduction process is very simple and cost effective. The removal of oxygen containing functional groups of GO has been confirmed by UV-vis, Fourier transform infrared and X-ray photoelectron spectroscopy analysis. Morphological characterization of rGO has been performed by atomic force and transmission electron microscopy analysis. Electrochemical performances of rGO have been evaluated by cyclic voltammetry (CV), charge-discharge and electrochemical impedance spectroscopy techniques. The specific capacitance (SC) of rGO has been found to be 137 Fg(-1) at a current density of 1.3 A g(-1). The retention in SC is more than 98% after 1000 charge-discharge cycles suggesting long-term electrochemical cyclic stability as supercapacitor electrode materials.

Macromolecular Materials and Engineering

Nanomaterials for Electrochemical Energy Storage Devices, 2019

Molten-salt etching of Ti3AlC2 MAX phase offers a promising route to produce 2D Ti3C2Tz (MXene) n... more Molten-salt etching of Ti3AlC2 MAX phase offers a promising route to produce 2D Ti3C2Tz (MXene) nanosheets without the need for hazardous HF. However, molten-salt etching generally results in MXene clays that are not fully exfoliated or water-dispersible, thus preventing nanosheet processing. This occurs because molten-salt etching generally results in a high level of -F terminal functionalities that render the MXene clay hydrophobic. Here, we demonstrate a molten salt (SnF2) etching method that, for the first time, produces water-dispersible Ti3C2Tz nanosheets without the need for HF. In molten salt etching, SnF2 diffuses between the layers during etching to form AlF3 and Sn as byproducts; Sn spheres form internally and separate the layers. The stable, aqueous Ti3C2Tz dispersion yields a ζ potential of -31.7 mV, because of -OH terminal groups introduced by KOH washing. X-ray diffraction and electron microscopy confirm the formation of Ti3C2Tz etched clay with substantial d-spacing ...

RSC Adv., 2015

A boron doped NiO/Fe3O4 nanostructure was successfully synthesized by a facile one-step hydrother... more A boron doped NiO/Fe3O4 nanostructure was successfully synthesized by a facile one-step hydrothermal method and used as the positive electrode material in asymmetric supercapacitor.

Nanoscale

Titanium carbide/reduced graphene oxide (Ti3C2Tz/rGO) gels were prepared by a one-step hydrotherm... more Titanium carbide/reduced graphene oxide (Ti3C2Tz/rGO) gels were prepared by a one-step hydrothermal process. The gels show a highly porous structure with a surface area of ~224 m2/g and average pore...