الفهرس 
Introduction and theoretical backgroundOnly 14 pages are availabe for public view
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Abstract
In recent years, Due to the growing energy demand, which causes the disastrous high exhaustion of fossil fuel, the search for clean and renewable energy sources has become an urgent necessity to keep pace with industrial development and preserve the depleted environment. Hence, it is necessary to work on the development of energy storage devices along with the search for new energy sources. Among these various energy storage devices, supercapacitors (SCs) is a prominent place which highly interests the researchers, as a result of their unique properties such as their safety, especially if compared with batteries, super-extended cycling life, low processing temperature, and ultra-high power density. Unfortunately, SCs’ practical applications suffer from their low energy density. Consequently, as a matter of brevity, scientific research aims to obtain a device with high energy without sacrificing its high power and other unique properties.
In this thesis, we demonstrate an easy and efficient hydrothermal approach for growing nanostructured materials of some transition metal oxides and sulfides for supercapacitor applications. In this regard, the concise aspects of supercapacitors in terms of charge storage mechanisms and the recent progress in the design and fabrication of electrode materials as well as energy-related performance were described using analysis techniques which can be divided to physical characterization, such as X-ray diffraction, X-ray photon spectroscopy, Scanning electron microscope and transmission electron microscope, and electrochemical characterization for both 3-electrode system and 3-electrode system such as cyclic voltammetry, galvanostatic charge-discharge, electrochemical impedance spectroscopy.
We dealt with different methods for preparing manganese oxide on different substrates, including the flexible substrate, such as carbon clothe and also on nickel foam, and comparing the results
Also we adopt a facile effective process for constructing of MnS prepared in situ with Ni2S3 and NiS directly on nickel foam, named MNE, to obtain a novel binder-free high conductive electrode with superb echinocactus-like morphology. The novel electrode gives ultra-high results when examined as an electrode for supercapacitor application.
Additionally we adopt a feasible method to enhance the electrochemical performance of (MnO2) by incorporating nanostructured MnO2 with an underlying conductivity-supporter reduced graphene oxide (rGO). In this chapter, nanoflakes-like structured MnO2/rGO was prepared and study different concentration of GO via a facile one-step hydrothermal method and choosing the best concentration. The presence rGO can offer a matrix for MnO2 nano-spheres suggesting an efficient way to enhance the conductivity. It does not only adapt to the nanoflakes MnO2by preventing its aggregation, but also offers a large electrode / electrolyte interface for the redox reactions. Therefore, the structure of MnO2/rGO markedly enhanced electrochemical performance as an electrode material for supercapacitor applications. Suggesting that, introducing carbon materials such as (rGO) is an efficient way to improve the electrochemical performance of metallic compounds for energy storage applications.