由於全球快速發展，人類對於石化燃料的需求也日益加增，這會對於環境有著嚴重的汙染問題，因此開發能源儲存裝置是一個很重要的議題。相較於傳統電容，超級電容有更多的能量密度，而相較於一般電池，超級電容器有較高的功率密度、快速充放電且有較長的生命週期，但其能量密度較一般電池來的低，因此提升超級電容能量密度是目前主要方向。
能量儲存與轉換是一個重要議題，超級電容的相關研究也更加重要，而超級電容根據不同的電荷儲存方式又可分為電雙層電容與擬電容，在此研究中，選擇氧化亞銅為擬電容材料，本實驗使用濕式化學法將銅離子(Cu2+)還原成氧化亞銅，藉由有無使用形貌控制劑PVP以及使用不同還原劑達到製備方形、圓形與八面體形氧化亞銅奈米粒子，再透過改變鹼濃度、還原劑與溶劑劑量製備出不同尺寸的氧化亞銅奈米粒子，從實驗結果得知氧化亞銅奈米粒子尺寸越小，比電容值有變大的趨勢，並且八面體形相對於方形與圓形有更高的比電容值；電雙層電容以氧化石墨烯為材料，不同尺寸氧化石墨烯具有不同含量的含氧官能基，透過其性質將氧化石墨烯分類，從實驗結果得知小片氧化石墨烯，比電容值較大，最後將氧化亞銅與氧化石墨烯複合，其比電容值沒有上升，但其穩定度有提高趨勢。

With the rapid global development, humanity’s demand for fossil fuels has reached unprecedented levels resulting in environmental problems. Development of energy storage devices is expected to play an important role recently. Supercapacitors have attracting great attention owing to its high energy densities compared to capacitors. Additionally, Supercapacitors have some distinct advantages compared to batteries such as higher power density and rapid charge discharge rate, as well as excellent cycle stability. However, the energy density of supercapacitors is still lower than that of battery. In this regard, enhancing energy density of the supercapacitor is the main theme of current research.
Supercapacitors are expected to play an important role. In our study, Cu2O have been chosen as pseudocapacitive materials. We synthesized Cu2O nanocrystals by reduction of Cu2+ through wet chemical method. Cu2O nanocrystals such as cubes, spheres, and octahedra have been synthesized by the addition of PVP or changing reductant from ascorbic acid to hydrazine hydrate. Furthermore, by adjusting the base concentration, the amount of solvent and the amount of reductant, we can obtain different sizes of Cu2O nanocrystals. According to our results, it was found that when the size of Cu2O nanocrystals decreases, the specific capacitance of Cu2O nanocrystals increase. Among the different morphology, Cu2O with the octahedral morphology shows the highest specific capacitance compared to cubic and spherical structures. Graphene oxide has been regarded as a good material of EDLC. In this study, we tested the effect of the sheet size of GO on the performance of EDLC made of GO as the active material. Size fractionation of graphene oxide sheets is based on the selective precipitation of GO sheets by adjusting the pH value. Small sized GO shows high specific capacitance compared with large sized GO. The composite of small sized GO with Cu2O nanocrystals did not show higher specific capacitance but with better capacity retention.

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