Search

For modern high‐tech flexible energy storage devices, it becomes important to synthesize micro‐/nanostructures as per the required shape and morphology with superior physical and electro‐active characteristics. This work shares the fabrication and characterization of ZnSn(OH)6 (Zinc hydroxystannate [ZHS]) prepared by facile microwave‐assisted technique and furthermore converted into flexible sheets by employing lignocelluloses (LC) known as natural fibers, collected from Carica papaya leaf petiole as a substrate to provide the flexible matrix. X‐ray diffraction measurements confirm the successful crystalline structure of ZHS. Scanning electron microscopy and transmission electron microscopy showed the solid spherical structure of ZHS microspheres. Fourier transform infrared spectrometry and Raman spectroscopy confirmed the composite formation of ZHS and LC‐based composite sheets (ZHS/LC sheets). Electrochemical measurements that is, cyclic voltammetry (CV), Galvanostatic charge/discharge, and electrochemical impedance (EIS) spectroscopy revealed the electroactive behavior of ZHS/LC paper sheets as working electrode for energy storage applications. CV measurements revealed the specific capacitance of 100 F/g and EIS measurements confirmed the decrease in the resistance of LC fiber after the growth of ZHS microspheres. Presented flexible ZHS based paper sheets will be highly feasible for the modern bendable/flexible/disposable energy storage applications. [ABSTRACT FROM AUTHOR]

Metal sulfide-based electrodes played a vital in energy storage applications due to novel characteristics, i.e., facile synthesis, relatively higher electronic conductivity and fast switching between redox states. This study presents the synthesis of chromium sulfide and reduced graphene oxide (rGO)-based electrodes in parallel to structural, morphological and electrochemical characterizations performed for supercapacitor applications. Individual chromium sulfide and reduced graphene oxide reveal the pseudocapacitive behavior in cyclic voltammetry (CV) curves with the maximum specific capacitance of 522.84 and 3.77 F/g, respectively, at the scan rate of 5 mV/s. Galvanostatic charge–discharge (GCD) measurements showed that Individual chromium sulfide exhibited a good specific capacitance of 710.90 F/g and energy density of 24.68 Wh/Kg at the applied current density of 3 mA/cm2, while the power density of 1028.81 W/Kg at 6 mA/cm2. CV curves of the asymmetric system consisting of chromium sulfide with reduced graphene oxide also revealed the pseudocapacitive behavior. The specific capacitance through CV curves has been found as 24.53 F/g at 10 mV/s, while a specific capacitance from GCD profile has been measured as 26.41 F/g at a current density of 4 μA/cm2. Moreover, the power density of the asymmetric system has been found as 780.35 W/Kg and indicated a suitable electrode structure for supercapacitor applications. This study is a first attempt to present the development of asymmetric cell of rGO and chromium sulfide-based electrodes which is highly feasible for high power density in parallel to reasonable energy density as per the demand of modern energy storage devices. [ABSTRACT FROM AUTHOR]

Functional materials, in the combination of lignocelluloses, known as natural fibers, with oxide materials, can result in cultivating functional properties such as flexibility, relativity good electrical conduction, good electrical charge storage capacity, and tunable electric permittivity. This study presents the morphological, dielectric, and impedance properties of lignocellulose–lead oxide (LC/PbO2) composite sheets electrodeposited with silver metallic nanoparticles for various time spans. The uncoated samples show a rather simple behavior where the impedance data fit well to the two-system model with different relaxation times. On the other side, the impedance spectra of the electrodeposited sample have varying features, which mainly depend upon the deposition thickness of the Ag particles. The common feature is the drift of conductive species, as seen from the straight-line behavior in the Nyquist plots, which were fitted using a Warburg element in the equivalent circuit model. [ABSTRACT FROM AUTHOR]

Composite materials and their applications constitute a hot field of research nowadays due to the fact that they comprise a combination of the unique properties of each component of which they consist. Very often, they exhibit better performance and properties compared to their combined building blocks. Graphene oxide (GO), as the most widely used derivative of graphene, has attracted widespread attention because of its excellent properties. Abundant oxygen-containing functional groups on GO can provide various reactive sites for chemical modification or functionalization of GO, which in turn can be used to develop novel GO-based composites. This review outlines the most recent advances in the field of novel dyes and pigments encompassing GO as a key ingredient or as an important cofactor. The interactions of graphene with other materials/compounds are highlighted. The special structure and unique properties of GO have a great effect on the performance of fabricated hybrid dyes and pigments by enhancing the color performance of dyes, the anticorrosion properties of pigments, the viscosity and rheology of inks, etc., which further expands the applications of dyes and pigments in dyeing, optical elements, solar-thermal energy storage, sensing, coatings, and microelectronics devices. Finally, challenges in the current development as well as the future prospects of GO-based dyes and pigments are also discussed. This review provides a reference for the further exploration of novel dyes and pigments. [ABSTRACT FROM AUTHOR]

In recent era of modern and bendable technology, energy dearth arises as a paramount subject around the globe with a dire demand of flexible and lightweight energy storage devices. This study targets fabrication of reduced graphene oxide (rGO) and utility of abundantly available, cost effective, and environment friendly lignocelluloses (LC) fibers extracted from Carica papaya source, as a binder to bind active material (rGO) as robust and compact paper sheet. Fabricated samples were analyzed by X-ray diffraction for crystallographic analysis, Scanning electron microscopy, Transmission electron microscope for morphology, Fourier transform infrared spectroscopy for structural bonding, and Raman spectroscopy for vibrational modes. Robust and bendable rGO/LC paper electrode was tested for energy storage application by employing in different characterizations, i.e., cyclic voltammetry for capacitive behavior, galvanostatic charge–discharge for symmetric EDLC, and electrochemical impedance spectroscopy for resistive charge kinetics, respectively. rGO/LC composite sheet employed as working electrode in 3-electrode CV measurements and revealed specific capacitance of 591 F/g at a scan rate of 5 mV/s by keeping the undistorted shape of voltammograms at higher scan rates which present it as a suitable candidate for modern flexible and energy storage devices. rGO/LC-based symmetric cell revealed the highest specific capacitance of 228 F/g at applied current density of 0.1 A/g, the energy density of 6.3 Wh/kg, and power density of 129 W/kg, respectively. rGO/LC-based symmetric cell confirmed the cycling stability by revealing capacitance retention of 82% after 200 cycles. It can conclude that biomass-based rGO paper sheet can be a potential candidate as environmentally safe with remarkable electrochemical activity in energy storage applications. [ABSTRACT FROM AUTHOR]

Unconventional and alternative resources are proved incredibly useful for flexible and bendable energy storage devices to meet the demand of modern disposable and bendable technology. Nickle hydroxide [Ni(OH)2] based composites are considered as high-performance electrodes for supercapacitor and batteries applications due to high specific capacitance at higher scan rates. This study presents the fabrication Ni(OH)2 and incorporation of lignocelluloses(LC) fibers as binders to address the inherent rigid structure. Furthermore, electrically conductive properties are address by synthesis of composites with Polypyrrole and Polyaninline. X-Ray diffraction (XRD) results confirm the successful formation of nickel hydroxide whereas scanning microscopy results (SEM) reveal the nanoparticle morphology. Incorporation of LC fibers within Ni(OH)2 particles presented as compact and flexible composite paper electrodes which can be cut with help of scissor in any shape for bulk use. Fourier Transform Infrared (FTIR) confirmed the composite formation and cyclic voltammetry (CV) measurements were performed for all the fabricated samples to observe the electrochemical kinetics by which the best specific capacitance is shown by Ni(OH)2/PPy/LC i.e. 630 Fg−1. These fabricated composites can be used further as flexible electrodes in energy storage applications because of enhanced electrochemical properties. Presented flexible Ni(OH)2 based paper sheets will be highly feasible for modern bendable and disposable energy storage devices due to light-weight and environmentally safe characteristics. [ABSTRACT FROM AUTHOR]

Metal oxide based electrodes are attractive for energy storage applications with limited characteristics of flexibility due to inherent rigid structure. However, incorporation of flexible insulating matrix within metal oxide composites result in poor electrically conductive and energy storage characteristics. This study presents the fabrication of flexible MnO2 based composite electrodes prepared by incorporation of lignocelluloses (LC) fibers, directly collected from a self-growing plant, Monochoria Vaginalis. Furthermore electrodeposition of silver (Ag) nanoparticles was performed on LC/MnO2 in potentiostatic mode to address the electrically conductive characteristics. Morphology, structural, conductive and energy storage properties of fabricated electrodes are analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), impedance analyzer and potentiostat, respectively. SEM images clearly indicate the deposition of Ag nanoparticles on MnO2 nanorods embedded in LC fibers whereas FTIR results confirm the bonding of the functional groups. Cyclic voltammetry measurements showed efficient kinetics of LC/MnO2 after electrodeposition of Ag nanoparticles. The effects on electrical properties associated with blending MnO2 nanorods in lignocelluloses fibers and Ag deposition on MnO2 in LC/MnO2 are explored in wide frequency range between 10 Hz and 5 MHz. However, deposition of Ag nanoparticles on MnO2 nanorods surfaces acts as a conductive path and reduces the associated resistance. Incorporated flexibility in rigid structure of MnO2 and further improvements in conductive and energy storage characteristics will open the possibilities to be used as electrode in modern bendable energy storage devices. [ABSTRACT FROM AUTHOR]

V2O3 samples were successfully prepared using [VOSO4·xH2O] as the starting material by a template-free hydrothermal method with the addition of KBrO3. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV). The XRD result shows the rhombohedral structure for V2O3 with an average crystallite size in the range of 22 nm. With the increase in reaction time (6-8 h), the morphology of the samples changes from nano-flower to nano-ribbons as indicated by SEM micrographs. FTIR spectrum shows that the band at 1286 cm−1, related to C-OH stretching and OH bending vibrations and indicate the presence of residual hydroxyl groups. The electrochemical measurements show an excellent storage response, kinetics and reversibility of the electrode material. Further, good rate capability of the materials was also observed. [ABSTRACT FROM AUTHOR]

In era of modern technology, light-weight, flexible, low-cost and environmentally safe substrates/electrodes are highly feasible for application in disposable electronics and energy storage devices. This study presents morphological and dielectric characteristics of naked and polyaniline (PANI) coated lignocelluloses fibers, directly collected from self-growing plant, Typha Angustifolia. Impedance spectroscopy measurements performed in frequency range from 0.1 Hz to 10 MHz revealed increase of six orders magnitude in conductive properties of lignocelluloses fibers coated with polyaniline. Dielectric constant of polyaniline coated lignocelluloses fibers also increased by three to five orders magnitude and revealed weak frequency dependence. Presented morphological and dielectric investigations of directly collected and PANI coated lignocelluloses fibers will open possibilities to develop facile, low-cost, flexible and environment friendly paper substrates for energy storage and disposable electronic applications. [ABSTRACT FROM AUTHOR]

Flexible, lightweight, and environment friendly energy storage devices are in high demand of modern disposable technology. This study presents the coating of directly collected lignocelluloses fibers from self‐growing plant, Monochoria vaginalis with conducting layers of polypyrrole and polyaniline. Fabricated paper electrodes were conductive, electroactive, all‐organic constituents, flexible, and can be cut with help of scissor in any shape. Paper electrodes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis for morphology, structural, and thermal characteristics, respectively. Furthermore, fabricated paper electrodes were characterized by cyclic voltammetry to confirm the electroactive behavior and showed excellent electrochemical performance. Paper sheets comprising lignocelluloses fibers and polypyrrole coating (LC/PPy) were employed as electrodes of symmetric cell and showed specific capacitance of 230.35 Fg−1 at current density 0.25 mA g−1 for LC/PANI, while LC/PPy showed 9.042 W h kg−1 and 91.33 W kg−1 energy density and power density, respectively. This paper electrodes are highly feasible for environmentally safe and flexible energy storage applications, particularly in era of modern disposable technology. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47282. [ABSTRACT FROM AUTHOR]

In an era of modern smart technology, flexible electrodes are of great interest for different energy conversion as well as energy storage applications like solar cells, all solid-state batteries, and supercapacitors. Flexible metal oxide-based paper electrodes are advantageous in comparison to conventional electrodes due to their economical synthesis, biocompatibility, and environment-friendly characteristics. However, the electrical conductivity of paper electrodes is limited because of the insulating nature of natural fibers employed as a binder for the flexible matrix of metal oxides. The current study is an attempt to tune the electrical properties of lignocelluloses (natural fibers) and titanium dioxide (TiO 2) based paper electrodes by facile electrodeposition technique. The crystalline parts (e.g., TiO 2 , Ag, and Au) of the prepared composite sheets were characterized by XRD analysis while the surface morphology was studied by SEM. FTIR was used to characterize the organic matter in LC fibers by identifying various molecular stretching and vibrational modes of C, H, and O-containing molecules. Electric permittivity was measured as a function of electric field frequency at room temperature which revealed the value of 23. 5 (at 1 kHz) for the sample LC/TiO 2 /Ag 9000s indicating the best charge storing capability of the sample. Impedance analysis was employed to identify various charge carrier mechanisms active in the sheets. It was found through impedance analysis that there is an active diffusion-controlled impedance mechanism of Au-coated samples causing an increased conductivity via the ionic diffusion. This diffusion-controlled conduction was modeled by the Warburg element. The enhanced conductivity due to ionic diffusion makes these samples more useful as electrodes. Cyclic voltammetry (CV) measurements of the electrodeposited samples established the increase in conductive properties and efficient kinetics of LC/TiO 2 paper sheets. The current study suggests that Ag and Au-coated paper electrodes can be potential candidates for energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

Development of cost efficient, flexible and light weight paper electrodes for high-tech applications is high in demand in era of modern disposable technology. In this study α-MnO 2 nanorods were fabricated through hydrothermal method by varying growth time and further combined with lignocelluloses fibers extracted from self growing plant, Monochoria Vaginalis. Crystal structure, morphology and thermal properties of MnO 2 nanorods were characterized by X. Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Thermogravimetric Analysis (TGA), respectively. FESEM image analysis revealed the highest aspect ratio of 48.016 for 4 h treated MnO 2 sample and high purity level was confirmed by XRD. MnO 2 sample with high aspect ratio, relatively pure and larger yield was selected for incorporation of lignocelluloses fibers to fabricate flexible, light-weight and environmentally safe LC/MnO 2 composite paper sheet. Furthermore, LC/MnO 2 composite sheet was employed as working electrode in 2 M sodium sulfate electrolyte for cyclic voltammetry measurements. Presented LC/MnO 2 composite sheet revealed specific capacitances 117, 59, 39, 25 and 23 F/g at scan rates of 5, 10, 20, 50 and 100 mV/s, respectively. Incorporation of LC fibers within MnO 2 nanorods as binders will open the possibilities to fabricate the flexible paper electrode for application in supercapacitors and batteries due to facile synthesis, light-weight and environmentally friendly aspects. [ABSTRACT FROM AUTHOR]

In this research work, we have studied the effect of substitution of Sr on the structural, morphological and impedance spectroscopic properties of Zr 1−x Sr x TiO 4 (x = 0, 0.05, 0.10, 0.15 and 0.2), synthesized using sol-gel auto-combustion technique. The X-ray diffraction confirmed the orthorhombic phase. The Fourier transform infrared spectroscopy spectra confirmed that no organic content was present in the sample. Field emission scanning electron microscopic analysis reveals that the particle size reduces from 125 nm to 15 nm. Energy dispersive X-ray technique confirmed the presence of Zr, Ti, Sr and O in the matrix. Dielectric properties are measured at room temperature in the frequency range of 20 Hz to 20 MHz by using the impedance analyzer. Dielectric parameters have been studied by using Koop's theory and Maxwell-Wagner's Model. AC conductivity increases with the increase in frequency and with increasing Sr contents. The impedance plot shows the dominance of grain boundary resistance. Dielectric relaxation process has been studied using Modulus plot. [ABSTRACT FROM AUTHOR]