## 1 Introduction  
In recent years, sustainable energy and green energy systems get considerable attention to meet the increasing demand for energy throughout the world. Much effort has been invested to extend renewable energy sources [1; 2], for example, rechargeable batteries and supercapacitors [3; 4; 5] are the main focus for research and get considerable attraction as energy-storage devices. Recently, supercapacitor received considerable attention, due to some of its interesting and beneficial advantages, like a long life time, high power density, and fast charge-discharge process. The electrochemical classification of a supercapacitor is based on charge-discharge progress and also on energy storage mechanisms, which can be classified into two types: Electrochemical double layer capacitors and pseudo-capacitors: (1) The electrochemical double layer capacitors can store energy directly by ion adsorption at the interface of the electrode/electrolyte and the main electrodes are carbon based material; (2) the pseudo-capacitors use the redox-active materials i.e., metal oxide-based material and conductive polymers, as electrode material allow the insertion redox reaction for both surface, as well at bulk state, and through fast surface redox reactions for storing energy [6; 7]. The performance of supercapacitors is mainly connected with the properties of the electrode material. Generally, three types of electrode materials are being used in a supercapacitor: Carbonaceousmaterials, transition metal oxides, and conducting polymer materials. Carbon-based materials, such as the typical materials of double-layer capacitors have a relatively lower specific capacitance and lower energy density, which hinders its practical application. In contrast, the metal oxides, as pseudo-capacitance materials, preserving much higher capacitance owing to the more charge storage at surface, get great interest and are widely investigated, due to their high theoretical capacitance for supercapacitors. The fabrication of these compounds, and especially oxides materials with diverse structures and morphologies, have attracted significant interest in material science and also at an industry level. Recently, efforts have also been made in the synthesis of binary component materials to upgrade the characteristics of materials and to enhance their characteristic properties beyond each individual component. Therefore, tremendous efforts have been devoted to the synthesis and fabrication of transition metal oxides, such as NiO [8; 9; 10], Fe\({}_{2}\)O\({}_{3}\)[11; 12], MnO\({}_{2}\)[13; 14; 15], Co\({}_{3}\)O\({}_{4}\)[16; 17; 18; 19], due to their high energy density, low cost, and environmental friendliness. Recently, cobalt sulfides and nickel sulfides, as new transitional metal sulfide electrode materials with high electrical conductivity and with superior electrochemical performances, have been investigated for pseudocapacitors [20; 21]. However, the chemical and physical properties of transition metal sulfides are directly related to surface morphology, structure, and the size of the materials. The fabrication of these compounds, and especially sulfides material similar to oxides materials with diverse structures and morphologies, have attracted significant interest for developing electrode materials for energy storage devices [22]. Up until now, different types of structures, with a diverse morphology of Ni/Co sulfide, such as nanosheets [22], porous aerogels [23], urchin-like structures [24], have been reported. More importantly, the nanotube feature structures shows promising electrochemical performances with an increased rate of capability, as they provide an easy way for electrolyte penetration into active electrode material from the inner nanotube surface and in reducing the inactive electroactive surface area. As a result, a more electroactive surface area of electrode materials contribute to the electrochemical performances of the supercapacitors [25].