CO2雷射誘導石墨烯複合 MnO2/MoS2應用於超級電容器之研製

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2023

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超級電容器(Supercapacitor)根據電荷儲存機制能夠分成電雙層電容器(Electrical double-layers capacitor, EDLC)、擬電容器(Pseudocapacitor)以及混合式超級電容器(Hybrid supercapacitor, HSC)三大類。相比於傳統的電容器能提供更優異的比電容值、循環穩定性以及更良好的充放電效率,故已成為近年來最重要的儲能元件之一。雷射誘導石墨烯(Laser-induced graphene, LIG)是一種新型的石墨烯製備方式,其具有低成本、製程簡易且可大規模生產等獨特優點。在聚醯亞胺(Polyimide, PI)上製備的LIG可形成多孔的石墨烯結構,以提供高比表面積之電極材料。雖然目前儲能領域的研究已廣泛使用LIG與單一材料進行複合,但卻沒有文獻同時使用二氧化錳(MnO2)及二硫化鉬(MoS2)進行LIG複合材料的開發。因此,本研究利用複合電鍍製程在LIG表面同時沉積MnO2與MoS2以開發一款新型的LIG-MnO2/MoS2電極材料,製備出具有高活性位點及優異比電容值的LM60M0.5電極材料。根據恆電流充放電(Galvanostatic Charge-Discharge, GCD)量測結果顯示,LM60M0.5在電流密度為0.5 mA/cm2下的比電容值為389.4 mF/cm2,相比純LIG (5.08 mF/cm2)與LM60 (317.91 mF/cm2),其比電容值分別提升76.7及1.2倍。此結果證實LIG透過MnO2電鍍60 min製程能有效提升LM60電化學性能,而LM60複合電鍍MoS2可進一步提升LM60M0.5電化學性能。此外,當電流密度增加到5 mA/cm2時LM60M0.5仍保有51.3 %的倍率性能,並且LM60M0.5電極材料在 5 mA/cm2的電流密度下經過6000次充放電循環後仍具有97.3 %的電容維持率,而在399.74 mW/cm2的功率密度下具有24.34 μWh/cm2的能量密度。此外,將本研究的實驗結果與目前文獻中類似材料進行比較,證實本研究所開發的LM60M0.5材料具有高比電容特性,有望成為有潛力的超級電容器電極材料。最後,為了驗證實際應用能力,使用LM60M0.5作為正極材料、LIG-AC作為負極材料,開發一款混合式超級電容器,並點亮LED燈與排列有NTNU ME圖樣的88顆並聯紅光LED燈,也透過相同方式成功驅動計算機56秒,以證實本研究所開發之混合式超級電容器具有作為儲能元件的實際應用能力。
Supercapacitors can be divided into three main categories based on their charge storage mechanisms: Electrical double-layer capacitors (EDLCs), Pseudocapacitors, and Hybrid supercapacitors (HSCs). Compared to traditional capacitors, they offer superior specific capacitance, cyclic stability, and better charge-discharge efficiency, making them one of the most crucial energy storage devices in recent years. Laser-induced graphene (LIG) is a novel method for graphene preparation, which offers unique advantages such as low cost, simple processing, and scalability for mass production. When prepared on polyimide (PI), LIG forms a porous graphene structure, providing a high specific surface area for use as an electrode material. While research in the energy storage field has extensively employed LIG in composites with individual materials, there is currently no literature on the development of LIG composite materials using both manganese dioxide (MnO2) and molybdenum disulfide (MoS2). Therefore, this study utilizes a composite electroplating process to simultaneously deposit MnO2 and MoS2 on the surface of LIG to develop a new type of LIG-MnO2/MoS2 electrode material, creating an electrode material labeled as LM60M0.5, which exhibits high active sites and excellent specific capacitance. According to the Galvanostatic Charge-Discharge (GCD) measurements, the specific capacitance of LM60M0.5 at a current density of 0.5 mA/cm2 is 389.4 mF/cm2. This represents a 76.7-fold increase compared to pure LIG (5.08 mF/cm2) and a 1.2-fold increase compared to LM60 (317.91 mF/cm2). This result confirms that the electroplating process of LIG with MnO2 for 60 minutes effectively enhances the electrochemical performance of LM60. Furthermore, the composite electroplating of MoS2 on LM60 further improves the electrochemical performance, resulting in LM60M0.5 electrode material. Furthermore, even at a higher current density of 5 mA/cm², LM60M0.5 maintained 51.3% of its rate capability. After 6000 charge-discharge cycles at 5 mA/cm², LM60M0.5 retained 97.3 % of its capacitance, and it exhibited an energy density of 24.34 μWh/cm² at a power density of 399.74 mW/cm². Comparing these results with similar materials from existing literature demonstrated that the developed LM60M0.5 material possessed high specific capacitance properties and held promise as a potential electrode material for supercapacitors. Finally, to verify its practical application capability, LM60M0.5 was utilized as the positive electrode material, while LIG-AC served as the negative electrode material, to develop a hybrid supercapacitor. This hybrid supercapacitor successfully illuminated LED lights and powered an array of 88 parallel-connected red LEDs arranged in the pattern of NTNU ME. Furthermore, using the same method, the hybrid supercapacitor successfully powered a computer for 56 seconds, affirming the real-world energy storage application potential of the hybrid supercapacitor developed in this study.

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雷射誘導石墨烯, 二氧化錳, 二硫化鉬, 高比表面積, 超級電容器, Laser-induced graphene, Manganese dioxide, Molybdenum disulfide, High specific surface area, Supercapacitor

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