Search

Vanadium pentoxide (V2O5) based electrodes for energy storage devices have captured sizeable attention in the past decade owing to their attractive physiochemical features. In the present work, flaky structured V2O5 was prepared using a single step hydrothermal route. The results from analytical investigations hold up well with the formation scheme proposed. The flaky morphology of V2O5 facilitates additional pathways for electron transport and effective ion access. When employed as a supercapacitor electrode in a neutral electrolyte, this flaky V2O5 electrode demonstrates a specific capacitance of 472 F g−1. Besides, it retains maximum capacitance at higher current density confirming its good rate performance. An asymmetric type supercapacitor using flaky V2O5 as positive electrode and activated carbon as negative electrode exhibits specific capacitance of 69 F g−1. This device shows energy density of 10 W h kg−1 within the operational window of 1 V. [ABSTRACT FROM AUTHOR]

Zinc cobalt oxide (ZnCo2O4) microspheres are prepared at three different hydrothermal process temperatures (100 °C, 130 °C, and 160 °C) assisted with urea. XRD studies reveal the spinel face-centered cubic (Fd3m) structure of ZnCo2O4 microspheres. The optical and vibrational properties of the product are characterized by photoluminescence and FTIR studies. The strong near-band edge emission peak observed at 392 nm corresponds to the direct recombination of the exciton-exciton collision process for all three synthesized products; SEM analysis reveals the complete growth stage of spherical ZnCo2O4 microspheres at three different temperatures. The electrochemical properties of synthesized ZnCo2O4 microspheres are analyzed by cyclic voltammetry, electroimpedance spectroscopy, and galvanostatic charging and discharging studies. ZnCo2O4 microspheres (SH3-160 °C) exhibit the superior specific capacitance of 500 F/g at 0.75 A/g current density and retain their specific capacitance of 80% at current density 2 A/g. ZnCo2O4 microspheres (SH3-160 °C) may be considered as a good candidate as electrode in supercapacitor applications. [ABSTRACT FROM AUTHOR]

Metal-doped tin oxide is gathering interest in the field of energy storage and power supply devices, particularly in supercapacitors applications. In the present study, we adopt a hydrothermal method to synthesis SnO2, Zn-SnO2, Ag-SnO2 nanoparticles at suitable conditions of temperature, pH, reaction time, and capping agents (CTAB). SnO2, Zn-SnO2, Ag-SnO2 nanoparticles were synthesized at 160 °C for 12 h and characterized by employing X-ray Diffraction to confirm the regular crystalline formation with tetragonal structure. Initial analyses by employing CV and GCD results exhibited specific capacitance of 308.2 Ag−1 for Ag-SnO2 nanoparticles at current density 0.5 A/g and can be considered as suitable candidate as positive electrode for supercapacitor device applications. [ABSTRACT FROM AUTHOR]

NiO/NiSnO3 nanocomposite synthesis was accomplished by a hydrothermal method. The role of polyvinylpyrrolidone and experimental parameters in the configuration of NiO/NiSnO3 nanocomposite was studied by employing standard characterization techniques. Electrochemical properties were demonstrated by adopting cyclic voltammetry, electro-impedance spectra and galvanostatic charging and discharging studies. All the obtained products have contact resistance Rct of 0.72 Ω at low frequency arising from the resistance between the working electrode and the electrolyte. The NiO/NiSnO3 nanocomposite superior properties may arise from nanosized rod morphology due to their inherent properties having a significant impact on their electrochemical properties. The specific capacitance for RSA3 can be estimated as 524 F/g at a current density of 0.5 A/g. [ABSTRACT FROM AUTHOR]

To accomplish superior performance in supercapacitors, a fresh class of electrode materials with advantageous structures is essential. Owing to its rich electrochemical activity, vanadium oxides are considered to be an attractive electrode material for energy storing devices. In this work, vanadium pentoxide (V2O nanostructures were prepared using surfactant (CTAB)-assisted hydrothermal route. Stacked V2O5 sheets enable additional channels for electrolyte ion intercalation. These stacked V2O5 nanosheets show highest specific capacitance of 466Fg at 0.5Ag. In addition, it exhibits good rate capacity, lower value of charge transfer resistance and good stability when used as an electrode material for supercapacitors. Further, an asymmetric supercapacitor device was assembled utilizing the stacked V2O5 sheets and activated carbon as electrodes. The electrochemical features of the device are also discussed. [ABSTRACT FROM AUTHOR]

Hydrothermal method was adapted to synthesis NiCoO nanoparticles by varying nickel and cobalt precursor concentration as 1:1, 1:2, and 1:3 ratios. X-ray diffraction (XRD) results revealed the spinel NiCoO structure belongs to $${\rm{Fd}}\overline {\rm{3}} {\rm{m}}$$ space group system with face-centered cubic crystal structure. Raman characteristic peaks observed at 495 and 654 cm explored E and A modes of spinel NiCoO product. Photoluminescence (PL) results revealed the hole recombination of Ni/Co ions from 3d-E and 3d-T electronic state of spinel NiCoO material. The characteristic Fourier transform infrared spectroscopy (FTIR) metal-oxygen bands appeared at 658 and 558 cm revealed the spinel-type crystal structure. SEM image revealed the NiCoO spherical nanoparticles formation with an average particle size of around 500 nm. The cyclic voltammetry studies revealed the estimated average specific capacitance value of NC3 (NiCoO spherical nanoparticles) as 542 F g relatively higher than NC1 and NC2. The electro impendence spectroscopy results explored the small arc formation in high frequency range and very low charge transfer resistance ( R ), which resulted high conductive active materials. The estimated specific capacitance for NC3 exhibited superior galvanstatic charging and discharging (GCD) characteristics with high specific capacitance of 294 F g at high current density of 1 A g and revealed that the obtained electrode is suitable for supercapacitor applications. Graphical abstract: Hydrothermal synthesis using an excess of Co source leads to smaller and more uniform particle size. This particle size and the slightly larger crystallite size formed in the materials leads to the improved electrochemical performance of the particles. [ABSTRACT FROM AUTHOR]

Abstract: In recent years, bioactive materials have become important in applications such as implantation, bone regeneration, scaffold, oral implantation and antioxidant materials because of their excellent bioactivity, biocompatibility, osteoconductivity and osteoinductive properties. When exposed to simulated body fluid, bioactive glasses have the ability to bond with both hard and soft tissues through the formation of a hydroxyapatite layer. Nowadays, nanotechnology is emerging as a nascent technology in all disciplines because of its high surface-to-volume ratio and unique properties at nanoscale length. The impact of nanotechnology in biomaterials is of interest because of the enhancement in their biocompatibility and bioactivity. In this investigation, the preparation of nanobioactive glasses by using different methods (such as sol–gel, hydrothermal and sonochemical) is discussed in detail. The structural and morphological characterisation of the prepared samples was made. [ABSTRACT FROM AUTHOR]