Hybrid supercapacitors (HSCs) that use the nickel hydroxide-graphene hybrid (NGH) as an anode material and reduced graphene oxide (rGO) as a cathode material are a promising HSC structure. The NGH electrode is synthesized by one-step, binder-free deposition of a micro-size hydroxide powder and graphite powder mixture on nickel foam by the nanoparticle deposition system (NPDS). The NPDS is classified as a vacuum kinetic spraying approach. The electrochemical performance of the NGH-10 electrode in a 3-electrode cell demonstrates a specific capacitance of 3400 F/g at 1 A/g. The NGH-10//rGO HSC displays a specific capacitance of 180 F/g at 1 mA/cm2 in a high operating potential from 0 V to 1.6 V. The NGH- 10//rGO HSC has an energy density of 64 Wh/kg @ 411 W/kg, and still 20 Wh/kg @ 8230 W/kg.

Hybrid supercapacitors (HSCs) that use the nickel hydroxide-graphene hybrid (NGH) as an anode material and reduced graphene oxide (rGO) as a cathode material are a promising HSC structure. The NGH electrode is synthesized by one-step, binder-free deposition of a micro-size hydroxide powder and graphite powder mixture on nickel foam by the nanoparticle deposition system (NPDS). The NPDS is classified as a vacuum kinetic spraying approach. The electrochemical performance of the NGH-10 electrode in a 3-electrode cell demonstrates a specific capacitance of 3400 F/g at 1 A/g. The NGH-10//rGO HSC displays a specific capacitance of 180 F/g at 1 mA/cm2 in a high operating potential from 0 V to 1.6 V. The NGH- 10//rGO HSC has an energy density of 64 Wh/kg @ 411 W/kg, and still 20 Wh/kg @ 8230 W/kg.

ZnS nanocrystals were prepared by the chemical co-precipitation method. The effect of annealing temperature (Ta) on the morphological, structural and optical absorption behavior was investigated using x-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), UV-vis spectroscopy, selected area electron diffraction (SAED) and Fourier transform infrared (FTIR) spectroscopy. Analysis of XRD patterns for as prepared and annealed samples showed that, increasing Ta leads to an increase in the crystallite size (D) from 2.67 to 19.6 nm. It is noticed that the obtained values of lattice parameters from HRTEM Images and SAED patterns are in good agreement with that deduced from XRD analysis. Furthermore, annealing process at 600 oC and 700 oC results, in complete phase transformation from as prepared ZnS cubic structure to ZnO hexagonal structure. Analysis of the XRD patterns, SAED, HRTEM and FTIR confirm this phase transition. Analysis of the optical absorption spectra indicates noticeable decrease in the direct band gap from 4.70 to 3.22 eV with increasing Ta. This behavior is attributed to the enhancement in crystallinity and the increase in particle size of ZnS nanoparticles. Moreover, UV photo-induced effect on the optical absorption edge was studied.

ZnS nanocrystals were prepared by the chemical co-precipitation method. The effect of annealing temperature (Ta) on the morphological, structural and optical absorption behavior was investigated using x-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), UV-vis spectroscopy, selected area electron diffraction (SAED) and Fourier transform infrared (FTIR) spectroscopy. Analysis of XRD patterns for as prepared and annealed samples showed that, increasing Ta leads to an increase in the crystallite size (D) from 2.67 to 19.6 nm. It is noticed that the obtained values of lattice parameters from HRTEM Images and SAED patterns are in good agreement with that deduced from XRD analysis. Furthermore, annealing process at 600 oC and 700 oC results, in complete phase transformation from as prepared ZnS cubic structure to ZnO hexagonal structure. Analysis of the XRD patterns, SAED, HRTEM and FTIR confirm this phase transition. Analysis of the optical absorption spectra indicates noticeable decrease in the direct band gap from 4.70 to 3.22 eV with increasing Ta. This behavior is attributed to the enhancement in crystallinity and the increase in particle size of ZnS nanoparticles. Moreover, UV photo-induced effect on the optical absorption edge was studied.

ZnS nanocrystals were prepared by the chemical co-precipitation method. The effect of annealing temperature (Ta) on the morphological, structural and optical absorption behavior was investigated using x-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), UV-vis spectroscopy, selected area electron diffraction (SAED) and Fourier transform infrared (FTIR) spectroscopy. Analysis of XRD patterns for as prepared and annealed samples showed that, increasing Ta leads to an increase in the crystallite size (D) from 2.67 to 19.6 nm. It is noticed that the obtained values of lattice parameters from HRTEM Images and SAED patterns are in good agreement with that deduced from XRD analysis. Furthermore, annealing process at 600 oC and 700 oC results, in complete phase transformation from as prepared ZnS cubic structure to ZnO hexagonal structure. Analysis of the XRD patterns, SAED, HRTEM and FTIR confirm this phase transition. Analysis of the optical absorption spectra indicates noticeable decrease in the direct band gap from 4.70 to 3.22 eV with increasing Ta. This behavior is attributed to the enhancement in crystallinity and the increase in particle size of ZnS nanoparticles. Moreover, UV photo-induced effect on the optical absorption edge was studied.

ZnS nanocrystals were prepared by the chemical co-precipitation method. The effect of annealing temperature (Ta) on the morphological, structural and optical absorption behavior was investigated using x-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), UV-vis spectroscopy, selected area electron diffraction (SAED) and Fourier transform infrared (FTIR) spectroscopy. Analysis of XRD patterns for as prepared and annealed samples showed that, increasing Ta leads to an increase in the crystallite size (D) from 2.67 to 19.6 nm. It is noticed that the obtained values of lattice parameters from HRTEM Images and SAED patterns are in good agreement with that deduced from XRD analysis. Furthermore, annealing process at 600 oC and 700 oC results, in complete phase transformation from as prepared ZnS cubic structure to ZnO hexagonal structure. Analysis of the XRD patterns, SAED, HRTEM and FTIR confirm this phase transition. Analysis of the optical absorption spectra indicates noticeable decrease in the direct band gap from 4.70 to 3.22 eV with increasing Ta. This behavior is attributed to the enhancement in crystallinity and the increase in particle size of ZnS nanoparticles. Moreover, UV photo-induced effect on the optical absorption edge was studied.

ZnS nanocrystals were prepared by the chemical co-precipitation method. The effect of annealing temperature (Ta) on the morphological, structural and optical absorption behavior was investigated using x-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), UV-vis spectroscopy, selected area electron diffraction (SAED) and Fourier transform infrared (FTIR) spectroscopy. Analysis of XRD patterns for as prepared and annealed samples showed that, increasing Ta leads to an increase in the crystallite size (D) from 2.67 to 19.6 nm. It is noticed that the obtained values of lattice parameters from HRTEM Images and SAED patterns are in good agreement with that deduced from XRD analysis. Furthermore, annealing process at 600 oC and 700 oC results, in complete phase transformation from as prepared ZnS cubic structure to ZnO hexagonal structure. Analysis of the XRD patterns, SAED, HRTEM and FTIR confirm this phase transition. Analysis of the optical absorption spectra indicates noticeable decrease in the direct band gap from 4.70 to 3.22 eV with increasing Ta. This behavior is attributed to the enhancement in crystallinity and the increase in particle size of ZnS nanoparticles. Moreover, UV photo-induced effect on the optical absorption edge was studied.

Capping free Zinc Sulphide nanoparticles were synthesis from aqueous solutions of Zinc Chloride (ZnCl2) and Sodium Sulphide (Na2S) in air at 70oC by co-precipitation method. The as-prepared and annealed samples were characterized by X-ray diffraction (XRD), UV-Vis absorption, scanning electron microscope (SEM), transmission electron microscope (TEM) and selected area electron diffraction (SAED). Analysis of XRD pattern indicates that the as prepared and annealed samples up to 300oC ZnS nano-crystallites have cubic zinc blend structure. Furthermore, annealing at 550oC, results in partial conversion of the initially cubic ZnS, to ZnS and ZnO Hexagonal phases as revealed by XRD patterns.SAED pattern for as-prepared ZnS reveals the polycrystalline nature. Furthermore, the lattice parameters determined from(XRD) and (SAED) patterns are in good agreement. Annealing of the ZnS nanoparticles in air in the temperature range, 150 – 550oC, leads to the increase in crystallite size from 2.14 to 18 nm accompanied by decrease in optical band gap(Egopt) from 3.98 to 3.3eV, for the as prepared and sample annealed at 550oC respectively. Analysis of TEM and SEM Images indicates that the ZnS nanoparticles tend to be nearly spherically shaped with narrow size distribution. Different times UV irradiation of ZnS aqueous solution results in increase in optical energy gap with the irradiation time. The observed photo brightening is explained in terms of the formation of ZnSO4 passivation layer via photon-assisted chemical reaction.

Capping free Zinc Sulphide nanoparticles were synthesis from aqueous solutions of Zinc Chloride (ZnCl2) and Sodium Sulphide (Na2S) in air at 70oC by co-precipitation method. The as-prepared and annealed samples were characterized by X-ray diffraction (XRD), UV-Vis absorption, scanning electron microscope (SEM), transmission electron microscope (TEM) and selected area electron diffraction (SAED). Analysis of XRD pattern indicates that the as prepared and annealed samples up to 300oC ZnS nano-crystallites have cubic zinc blend structure. Furthermore, annealing at 550oC, results in partial conversion of the initially cubic ZnS, to ZnS and ZnO Hexagonal phases as revealed by XRD patterns.SAED pattern for as-prepared ZnS reveals the polycrystalline nature. Furthermore, the lattice parameters determined from(XRD) and (SAED) patterns are in good agreement. Annealing of the ZnS nanoparticles in air in the temperature range, 150 – 550oC, leads to the increase in crystallite size from 2.14 to 18 nm accompanied by decrease in optical band gap(Egopt) from 3.98 to 3.3eV, for the as prepared and sample annealed at 550oC respectively. Analysis of TEM and SEM Images indicates that the ZnS nanoparticles tend to be nearly spherically shaped with narrow size distribution. Different times UV irradiation of ZnS aqueous solution results in increase in optical energy gap with the irradiation time. The observed photo brightening is explained in terms of the formation of ZnSO4 passivation layer via photon-assisted chemical reaction.

Capping free Zinc Sulphide nanoparticles were synthesis from aqueous solutions of Zinc Chloride (ZnCl2) and Sodium Sulphide (Na2S) in air at 70oC by co-precipitation method. The as-prepared and annealed samples were characterized by X-ray diffraction (XRD), UV-Vis absorption, scanning electron microscope (SEM), transmission electron microscope (TEM) and selected area electron diffraction (SAED). Analysis of XRD pattern indicates that the as prepared and annealed samples up to 300oC ZnS nano-crystallites have cubic zinc blend structure. Furthermore, annealing at 550oC, results in partial conversion of the initially cubic ZnS, to ZnS and ZnO Hexagonal phases as revealed by XRD patterns.SAED pattern for as-prepared ZnS reveals the polycrystalline nature. Furthermore, the lattice parameters determined from(XRD) and (SAED) patterns are in good agreement. Annealing of the ZnS nanoparticles in air in the temperature range, 150 – 550oC, leads to the increase in crystallite size from 2.14 to 18 nm accompanied by decrease in optical band gap(Egopt) from 3.98 to 3.3eV, for the as prepared and sample annealed at 550oC respectively. Analysis of TEM and SEM Images indicates that the ZnS nanoparticles tend to be nearly spherically shaped with narrow size distribution. Different times UV irradiation of ZnS aqueous solution results in increase in optical energy gap with the irradiation time. The observed photo brightening is explained in terms of the formation of ZnSO4 passivation layer via photon-assisted chemical reaction.