Electrochemical Capacitance Performance Of Cobalt And Nickel Metal Oxides And Hybrid Supercapacitors

In recent years, supercapacitors have attracted growing attention to the applicayion of electrical energy storage systems because of their higher specific power than batteries and higher specific energy than conventional capacitors. Now, it is the major reseach direction how to improve and enhance the performance of supercapacitors, such as specific capacitance,specific energy density and specific power density, and so on. The current reseach is focused on the the following two aspects: One is the further exploration for some materials with high specific capacitance, including the modification of the existed synthesis methods, the expansion of the electrochemical window, and the quest for some new electrode materials for supercapacitors; and the other is to enhance the power property, that is, to increase the specific power density within the maximum limit. The thesis can be divided into four parts:The purpose of the first chapter is to survey the fundamental principles, characterizations and applications of supercapacitors, especially the recent progress of researches on supercapacitors using carbon, transition-metal oxides and conducting polymers as electrode materials and the study of all solid-state and hybrid supercapacitors. Based on the above overviews, I put forth my purposes and some ideas to solve certain existed questions.The second chapter shows the synthesis and electrochemical capacitance performance of the mesoporous Co(OH)2 in 1 M KOH electrolyte. Mesoporous Co(OH)2 with the high specific area of 283 m2 /g and average pore size of 11 nm by means of the SDS as soft template and urea as precipitator was synthesized. Electrochemical studies revealed the the electrode prepared with such material exhibited a high specific capacitance of 341 F/g. The charge storage mechnism and the attribute to the measured capacitance were investigated. In addition, it had been investigated in extenso how the specific area and pore size affected the capacitance values and characteristics. And the frequency response of the material was also studied.