V.S. Kumbhar

Supercapacitive activities of potentiodynamically deposited nanoflakes of cobalt oxide (Co3O4) thin film electrode

In the present work, the Co3O4 thin films are successfully prepared via potentiodynamic electrodeposition method onto inexpensive stainless steel substrate. As-deposited films were heat treated at 623K for their conversion into Co3O4. These films were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) techniques. The X-ray diffraction (XRD) study revealed the formation of cobalt oxide (Co3O4) with cubic crystal structure. The FT-IR study supports the formation of Co3O4 material. The SEM image of Co3O4 film showed nanoflake-like morphology with an average thickness of 100 nm. Supercapacitive properties of Co3O4 thin film electrode were examined using cyclic voltammetry and charge-discharge techniques. The Co3O4 thin film electrode showed maximum specific capacitance of 365 Fg(-1) in 1M KOH electrolyte at the scan rate of 5 mV s(-1). The charge-discharge technique was employed to estimate the values of specific energy, power and coulombic efficiency as 64 W h kg(-1), 21.53 kW kg(-1) and 99%, respectively.

Wet chemical synthesis of WO3 thin films for supercapacitor application

Tungstic oxide (WO3) thin films have been synthesized by wet chemical method, i.e., successive ionic layer adsorption and reaction (SILAR) method. These films are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption techniques. The XRD pattern revealed the formation of polycrystalline WO3 films. Scanning electron micrographs demonstrate the three-dimensional aggregated irregular extended rod shaped morphology of WO3 thin films. The WO3 film showed a direct band gap of 2.5 eV. The WO3 film exhibited specific capacitance of 266 F·g−1 in 1 M Na2SO4 electrolyte at the scan rate of 10 mVs−1.

Electrochemical behavior of chemically synthesized selenium thin film

The facile and low cost simple chemical bath deposition (CBD) method is employed to synthesize red colored selenium thin films. These selenium films are characterized for structural, morphological, topographical and wettability studies. The X-ray diffraction (XRD) pattern showed the crystalline nature of selenium thin film with hexagonal crystal structure. The scanning electron microscopy (SEM) study displays selenium nanoparticles ranging from 20 to 475 nm. A specific surface area of 30.5 m(2) g(-1) is observed for selenium nanoparticles. The selenium nanoparticles hold mesopores in the range of 1.39 nm, taking benefits of the good physicochemical stability and excellent porosity. Subsequently, the electrochemical properties of selenium thin films are deliberated by cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques. The selenium thin film shows specific capacitance (Cs) of 21.98 F g(-1) with 91% electrochemical stability.

Modified chemical synthesis of porous α-Sm{sub 2}S{sub 3} thin films

Highlights: • A novel chemical route to prepare α-Sm{sub 2}S{sub 3} thin films. • A porous honeycomb like morphology of the α-Sm{sub 2}S{sub 3} thin film. • An application of α-Sm{sub 2}S{sub 3} thin film toward its supercapacitive behaviour. - Abstract: The paper reports synthesis of porous α-Sm{sub 2}S{sub 3} thin films using modified chemical synthesis, also known as successive ionic layer adsorption and reaction (SILAR) method. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), wettability and ultraviolet–visible spectroscopy (UV–vis) techniques are used for the study of structural, elemental, morphological and optical properties of α-Sm{sub 2}S{sub 3} films. An orthorhombic crystal structure of α-Sm{sub 2}S{sub 3} is resulted from XRD study. The SEM and AFM observations showed highly porous α-Sm{sub 2}S{sub 3} film surface. An optical band gap of 2.50 eV is estimated from optical absorption spectrum. The porous α-Sm{sub 2}S{sub 3} thin film tuned for supercapacitive behaviour using cyclic voltammetry and galvanostatic charge discharge showed a specific capacitance and energy density of 294 Fg{sup –1} and 48.9 kW kg{sup –1}, respectively in 1 M LiClO{sub 4}–propylene carbonate electrolyte.