Publications by authors named "Chowdari B"

The VB-air battery is currently known for its highest theoretical specific capacity, up to 4060 mA h g. This together with the excellent environmental compatibility and high security endues with promising application prospects for the battery. However, the self-discharge of the anode caused by hydrogen evolution corrosion results in a severe capacity loss during discharge.

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Garnet-type solid-state electrolytes (SSEs) show a promising application in solid-state Li batteries. Poor interfacial contact with lithium causing large interfacial impedance and dendrite penetration is a problem. Inspired by unique H/Li exchange of garnet electrolyte, we used an AgNO aqueous solution induced strategy to construct a lithiophilic layer in situ on the garnet surface without any specific apparatus.

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A facile and effective method to modify Li anode for Li-S cells by exposing Li foils to tetrahydrofuran (THF) solvent, oxygen atmosphere and trimethylsilyl chloride ((CH3)3SiCl) liquid in sequence is proposed. The results of SEM and XPS show the formation of a homogeneous and dense film with a thickness of 84 nm on Li metal surface. AC impedance and polarization test results show the improved interfacial stability.

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Exfoliated graphene oxide (EG)/MoO2 composites are synthesized by a simple solid-state graphenothermal reduction method. Graphene oxide (GO) is used as a reducing agent to reduce MoO3 and as a source for EG. The formation of different submicron sized morphologies such as spheres, rods, flowers, etc.

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Li-ion batteries (LIBs) are considered as the best available technology to push forward the production of eco-friendly electric vehicles (EVs) and for the efficient utilization of renewable energy sources. Transformation from conventional vehicles to EVs are hindered by the high upfront price of the EVs and are mainly due to the high cost of LIBs. Hence, cost reduction of LIBs is one of the major strategies to bring forth the EVs to compete in the market with their gasoline counterparts.

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Constructing three-dimensional (3D) architecture with oriented configurations by two-dimensional nanobuilding blocks is highly challenging but desirable for practical applications. The well-oriented open structure can facilitate storage and efficient transport of ion, electron, and mass for high-performance energy technologies. Using MoS2 as an example, we present a facile and effective hydrothermal method to synthesize 3D radially oriented MoS2 nanospheres.

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Combustion of magnesium in dry ice and a simple subsequent acid treatment step resulted in a MgO-decorated few-layered graphene (FLG) composite that has a specific surface area of 393 m(2)/g and an average pore volume of 0.9 cm(3)/g. As an anode material in Li-ion batteries, the composite exhibited high reversible capacity and excellent cyclic performance in spite of high first-cycle irreversible capacity loss.

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In the present study, we report the synthesis of a high-quality, single-crystal hexagonal β-Co(OH)2 nanosheet, exhibiting a thickness down to ten atomic layers and an aspect ratio exceeding 900, by using graphene oxide (GO) as an exfoliant of β-Co(OH)2 nanoflowers. Unlike conventional approaches using ionic precursors in which morphological control is realized by structure-directing molecules, the β-Co(OH)2 flower-like superstructures were first grown by a nanoparticle-mediated crystallization process, which results in large 3D superstructure consisting of ultrathin nanosheets interspaced by polydimethoxyaniline (PDMA). Thereafter, β-Co(OH)2 nanoflowers were chemically exfoliated by surface-active GO under hydrothermal conditions into unilamellar single-crystal nanosheets.

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In this work, maghemite (γ-Fe2O3) nanoparticles were uniformly coated on carbon nanofibers (CNFs) by a hybrid synthesis procedure combining an electrospinning technique and hydrothermal method. Polyacrylonitrile nanofibers fabricated by the electrospinning technique serve as a robust support for iron oxide precursors during the hydrothermal process and successfully limit the aggregation of nanoparticles at the following carbonization step. The best materials were optimized under a carbonization condition of 600 °C for 12 h.

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The compounds, CoN, CoO, and Co3O4 were prepared in the form of nano-rod/particles and we investigated the Li-cycling properties, and their use as an anode material. The urea combustion method, nitridation, and carbothermal reduction methods were adopted to prepare Co3O4, CoN, and CoO, respectively. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and the Brunauer-Emmett-Teller (BET) surface and density methods were used to characterise the materials.

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Electrospun carbon nanofibers (CNF) have been prepared at different calcination temperatures for a prolonged time (12 h) derived from electrospun polyacrylonitrile (PAN) membranes. They are studied as anode materials in lithium ion batteries due to their high reversible capacity, improved long-term cycle performance, and good rate capacity. The fibrous morphologies of fresh electrodes and tested samples for more than 550 cycles have been compared; cyclic voltammogram (CV) has also been studied to understand the lithium intercalation/deintercalation mechanism of 1D nanomaterials.

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In this work, the electrochemical performance of NiFe2O4 nanofibers synthesized by an electrospinning approach have been discussed in detail. Lithium storage properties of nanofibers are evaluated and compared with NiFe2O4 nanoparticles by galvanostatic cycling and cyclic voltammetry studies, both in half-cell configurations. Nanofibers exhibit a higher charge-storage capacity of 1000 mAh g(-1) even after 100 cycles with high Coulmbic efficiency of 100% between 10 and 100 cycles.

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InVO4 has attracted much attention as an anode material due to its high theoretical capacity. However, the effect of preparation methods and conditions on morphology and energy storage characteristic has not been extensively investigated and will be explored in this project. InVO4 anode material was prepared using five different preparation methods: solid state, urea combustion, precipitation, ball-milling, and polymer precursor methods.

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Zn2SnO4 nanowires have been synthesized directly on stainless steel substrate without any buffer layers by the vapor transport method. The structural and morphological properties are investigated by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical performance of Zn2SnO4 nanowires is examined by galvanostatic cycling and cyclic voltammetry (CV) measurements in two different voltage windows, 0.

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We report the synthesis of CuO material by molten salt method at a temperature range, 280 to 950 °C for 3 h in air. This report includes studies on the effect of morphology, crystal structure and electrochemical properties of CuO prepared at different temperatures. Obtained CuO was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area methods.

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Metal nitride (Ni(0.33)Co(0.67))N nanoparticles are prepared by nitridation using NiCo(2)O(4) as a precursor material by heating at 335 °C for 2 h in flowing NH(3) + N(2) gas and characterized by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), high resolution-transmission electron microscopy (HR-TEM), along with selective area electron diffraction (SAED) and X-ray absorption spectroscopy (XAS) techniques.

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Interconnected networks of CoMoO(4) submicrometer particles are prepared by thermolysis of polymer matrix based metal precursor solution. The material exhibited a high reversible capacity of 990 (±10) mAh g(-1) at a current density of 100 mA g(-1), with 100% capacity retention between 5 and 50 cycles. The improved electrochemical performance of CoMoO(4) submicrometer particles with interconnected network like morphology makes it promising as a high-capacity anode material for rechargeable lithium ion batteries.

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Mesoporous SnO(2) agglomerates with hierarchical structures and a high surface area were fabricated through a molten salt method. The SnO(2) demonstrated high photoelectric conversion efficiencies of 3.05% and 6.

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Lithium trivanadate (Li(1+x)V3O8) nanorods have been synthesized by the simple polymer precursor route using the polymer, polyvinyl pyrrolidone (PVP) as the complexing agent. Thermal behavior of the precursor has been studied by the differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and differential thermal analysis (DTA) techniques. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) studies confirm the formation of the compound.

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The Pechini type polymerizable complex decomposition method is employed to prepare LiTi(2)(PO(4))(3) at 1000 °C in air. High energy ball milling followed by carbon coating by the glucose-method yielded C-coated nano-LiTi(2)(PO(4))(3) (LTP) with a crystallite size of 80(±5) nm. The phase is characterized by X-ray diffraction, Rietveld refinement, thermogravimetry, SEM, HR-TEM and Raman spectra.

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