Development of Nickel Hydroxide/Oxide Composite for Application in Next Generation Electrochemical Capacitors
Kim, Brian Kihun
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With the world’s increasing energy demand and the depletion of fossil fuels, there is a growing demand for the development of alternative and clean energy sources. Batteries and fuel cell technologies have been cited as next generation technologies to provide sustainable energy; however, these technologies are insufficient in supplying high power in short time periods that can be produced by oil as an energy source. In contrast, electrochemical capacitors possess fast charging/discharging capabilities with high power output. As a result, the use of electrochemical capacitors in commercial applications has generated strong interest. Examples of commercial applications include emergency back-up power, consumer electronics, and hybrid vehicles. Commercially available electrochemical capacitors are based on carbonaceous materials with high surface area, excellent electrical conductivity, and wettability which statically store the charges in pores. In contrast, pseudocapacitive materials, namely transition metals, utilize fast reversible faradaic reactions on the surface of the materials which allow for greater energy storage than carbonaceous materials. Currently, many research activities are being focused on pseudocapacitive materials in an effort to enhance their energy storage capabilities. This thesis presents research on a pseudocapacitive material: nickel hydroxide/oxide hybrid. Also, it identifies the hybrid material’s lack of conductivity which can negatively impact its capacitive performance. An addition of carbon supports is recommended to enhance the conductivity. There are two parts to this study. The first study addresses the synthesis of the nickel hybrid structures through solvothermal process and calcination. The materials are thoroughly analyzed through physical and electrochemical characterizations. The issue of using the hybrid material as pseudocapacitor electrodes are identified at this stage. The second part of the study addresses the effect of different carbon additives in the nickel hybrid material. Commonly known carbon additives are incorporated into the nickel hybrid material and analyzed through electrochemical characterization to distinguish the best carbon support for the nickel hydroxide/oxide.