以回收碳纖維電極實現多功能儲能複合材料之可行性研究

Abstract

在這項研究中介紹了一種碳纖維回收方式，能夠將其製造成儲能設備以獲得更高的再利用價值。本研究利用濃硫酸進行碳纖維複合材料的回收作業並成功從中取得回收碳纖維，並且回收碳纖維的機械性能與初始碳纖維表現相似 (拉伸強度分別為322.4 MPa 和 321.2 MPa)；在電化學儲能機制的部分，回收碳纖維電極並不會因為本研究中所使用的回收方式產生影響。在比電容值的表現中，經過回收處理後的碳纖維表現有微幅上升(30.8 mF/g提升至42.7 mF/g)。 本研究將所取得之回收碳纖維結合改良的自動化局部高溫活化儀器(D70，600℃-70分鐘)及實驗室先前所研發的膠體電解質(Gel polymer)製作成超級電容，透過真空袋(PE)及環氧樹脂(Epoxy)進行多功能儲能複合材料的封裝。量測其最終成品的比電容值在5 mA/g的電流密度下，擁有最大比電容值3281 mF/g。 為了更符合實際應用層面，本研究亦針對了內部串疊進行研究。在將兩個單一元件進行內部串疊之後，其工作電位成功擴充至2 V並且將能量密度從1275.5 J/Kg提升至2500 J/Kg，達成提升儲能表現及工作電位的目的。最後將針對此多功能儲能複合材料進行機械性質測驗，透過施加不同大小的循環負載，測量其剛性的保留率，最後發現其在800 N的循環負載下，其材料剛性仍舊維持良好的表現。

In this study, we report a way to recycle carbon fibers and fabricate them into energy storage devices to create a new reuse method. First, by soaking the carbon fiber composite materials in sulfuric acid and it can obtain a recycled carbon fibers. The products based on recycled carbon fibers(RCF) showed similar mechanical performance to virgin carbon fibers-based products (tensile strengths are 322.4 MPa and 321.2 MPa , respectively); At energy storage mechanism, the recycled carbon fiber electrodes will not be affected by this recycled process. Moreover, the specific capacitance value of RCF was slightly increased from 30.8 mF/g to 42.7 mF/g. Then, the activation of recycled carbon fiber was carried out by improved activation instrument (D70, 600°C-70 minutes). The gel electrolyte fabrication method which was developed by the our lab. Finally, packaged with the PE bag and epoxy resin for multifunctional energy storage composite. The specific capacitance value of the final product was 3281 mF/g at 5 mA/g of current density . In order to be more practical to the application, this research also studies the tandem stack method. After connecting two single circuit, the working potential was successfully expanded to 2 V and the energy density increased from 1275.5 J/Kg to 2500 J/Kg. It successfully increase the energy storage ability and working potential. Finally, the mechanical properties of this product will be measured by observed the stiffness retention ratio. Furthermore, the stiffness retention have great performance after 800 N cyclic loading test.