الفهرس 
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Abstract
While significant attempts have been made in the past to produce large-performance fuel- cells and batteries of Lithium-ion, Because of their poor power capacity and high maintenance costs, they have been omitted from many applications. Supercapacitors have recently received a lot of attention due to their high charge/discharge rate, long life cycle, and high power density. Supercapacitors, on the other hand, have poor energy-density in general. The aim of this thesis research is to develop nickel cobaltite functionalized silver doped carbon xerogel –based supercapacitors with advantage large power- density (Pd), energy- density (Ed) and low production cost. Supercapacitors (SCs), also known as ultracapacitors or electrochemical- capacitors, are extremely porous materials that store energy as an electrical charge. The low energy density of supercapacitors is currently a significant limitation to their use in promising applications. Carbon xerogel and binary transition metal oxides are two promising materials for fabrication electrode for electric double-layer (EDL) supercapacitors and pseudo-capacitors.
Silver doped carbon xerogels have been synthesized from resorcinol and formaldehyde via a simple sol-gel method in presence of silver acetate. The silver doped carbon xerogels are further surface functionalized with different loadings of nickel cobaltite (1 wt. %, 5 wt. % and 10 wt. %) using a facile impregnation process. The morphology and textural properties of the obtained composites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen physisorption analysis. The silver doped carbon xerogels display a higher surface area and larger mesopore volume compared to the un-doped carbon xerogels. The hybrid composites have been utilized as electrode materials for symmetric supercapacitors in 6 M KOH electrolyte. Among all the hybrid composites, silver doped carbon xerogel functionalized with 1 wt. % nickel cobaltite (NiCo1/Ag-CX) shows the best supercapacitor performance: high specific capacitance (368 F.g─1 at 0.1 A.g─1), low equivalent series resistance (1.9 Ω), high rate capability (98.8% capacitance retention after 2000 cycles at 1 A. g─1), and high energy and power densities (50 Wh/Kg, 200 W/Kg at 0.1 A. g─1). The superior supercapacitive performance of NiCo1/Ag-CX is ascribed to its small catalytic particle size, uniform particle distribution and highly porous structure which contribute to abundant active sites and fast charge and ion transfer rates between the electrolyte and the active sites.
Keywords: supercapacitors; carbon xerogel; silver nanoparticles; nickel cobaltite; hybrid electrode materials; porous structure.