隨著科技發展，全球對能源依賴度逐漸增加，使化石燃料面臨短缺，因此再生能源及能源裝置的需求與重要性也日益增加。微型電容器具有良好的功率密度、快速充放電、良好的循環性能，使其被廣泛應用於儲能裝置。為了有效提升能量密度及滿足系統微小化，微型電容器的電極結構由平面2D轉變為3D結構，能在固定面積(footprint area)下提升活性材料負載量，以實現高性能超級電容器，將更適合應用於便攜式電子設備。 本研究利用二氧化錳/奈米多孔鎳材料製成高比表面積3D電極，能夠承載更多活性材料。首先透過雷射切割技術將發泡鎳(Nickel foam, NF)製備為3D指叉集電層，再將氧化鎳填充至發泡鎳大孔結構中，並透過燒結與還原形成高比表面積之奈米多孔鎳(Nanoporous-nickel, NPN)作為3D集電層，進一步利用水熱法將奈米片形貌氧化錳作為活性物質沉積於集電層上，進而製備成微型超級電容器。由SEM顯示NPN中商用發泡鎳之大孔洞結構已成功被填充且產生無數奈米孔隙，能使活性物質的質量負載由0.92 mg/cm2提升至23.8 mg/cm2。由電化學電性分析，MnO2/NPN於電流密度5 mA/cm2下比面積電容值為19.34 F/cm2，能量密度為671 μWh/cm2，比未填充之MnO2/NF性能高25倍。改良後的電極材料其優異的電化學性能歸因於NPN具有良好的導電網，及其高比表面積可提供活性材料超大負載空間，進而提升面積電容與能量密度。本研究利用簡便與低成本的方法製備出高比表面積的3D電極對微型儲能系統具有未來發展及應用的潛力。 ;With the development of science and technology, the world’s dependence on energy has gradually increased. Therefore, the needs on developing renewable energy and energy storage devices are drawing more and more research attention. Micro-supercapacitors (MSCs) possess excellent performance on power density, charging and discharging rate, and cyclic operation, making them widely used in various electronic devices. In order to achieve satisfactory energy density in miniaturized devices, the design of MSC electrode is changed from planar 2D to 3D structure. 3D structured electrode will provide higher surface area and volume for mass loading of active material within the fixed footprint area. The high-performance supercapacitors will be more suitable for applications in miniaturized electronic devices. In this work, MnO2/nanoporous nickel (NPN) materials are used to fabricate high specific surface area 3D electrode that facilitates higher mass loading of active materials. Nickel foam (NF) is first patterned into interdigital electrode using laser cutting technique. Next, the 3D nanoporous nickel (NPN) current collector is fabricated by filling NiO powder into NF interdigital electrode, followed by sintering in air and then reduction under H2 atmosphere. Active materials composed of nanosheet manganese dioxide (MnO2) are deposited on current collector via hydrothermal reaction to prepare the MnO2/NPN interdigital electrode of all-solid-state MSC. SEM images of NPN indicate that the pores in commercial NF have been successfully filled with nickel oxide, and the structure of electrode has transformed into nanoporous structure that possesses high specific surface area. The value of mass loading has increased from 0.92 mg/cm2 to 23.8 mg/cm2 compared to NF. The result of electrochemical analysis of MnO2/NPN shows an areal capacitance of 19.34 F/cm2 at 5 mA/cm2 current density and an energy density of 671 μWh/cm2, 25 times higher than that of MnO2/NF. The excellent electrochemical performance of MnO2/NPN’s areal capacitance and energy density can be mostly attributed to the combination of the enlarged loading area and the good electron conductive network within electrode. This study provides a simple and inexpensive method to prepare 3D electrode with high specific surface area and the performance of the MSC shows potential for future application in micro-energy storage systems.
