三維結構之微孔石墨烯於超級電容器之應用與研究;Three-dimensional electrode self-assembly of nanoporous graphene for the binder-free and high-performance supercapacitor

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Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/69207

Title:	三維結構之微孔石墨烯於超級電容器之應用與研究;Three-dimensional electrode self-assembly of nanoporous graphene for the binder-free and high-performance supercapacitor
Authors:	張鈞賀;Chang,Jun-He
Contributors:	能源工程研究所
Keywords:	石墨烯;超級電容;儲能;graphene;supercapacitor;energy storage
Date:	2015-10-06
Issue Date:	2015-11-04 17:30:29 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究製作並分析一種結合微米與奈米多孔性的石墨烯三維複合電極，並整合此電極於研製超級電容及其元件的特性研究。在製作上，首先利用碳材活化技術於石墨烯片層基面上形成奈米孔(約 3 nm)，並搭配凍乾技術，製作出可用於高性能超級電容器的三維微孔碳材。合成出的石墨烯，以不同溫度進行熱還原，探討其表面化態、物理及電化學性質，，而就一般疊層所製得的石墨烯電極來比較其超級電容特性，結果顯示以 400°C 還原後的樣品表現最佳，電容可達 247 F/g，而 600°C 及 800°C 的電容值相近(115 F/g)，也因此，在後續的進一步改質方法測試中，以 400°C 還原之樣品為討論主軸。在相較於一般疊層之本質石墨烯電極(電容 247 F/g)，活化後的奈米孔石墨烯之電容提升至 274 F/g(增益 111%)，而進一步的凍乾製程所形成的自組裝微孔電極，可進一步提升至 338 F/g(增益 137%)。此外，三微結構的石墨烯電容器，具有優異的電容維持率，僅經過活化後的奈米微孔之石墨烯電極經過 1500 次充放電測試後，維持率為 87%，與原始石墨烯電極無異，然而，結合奈米孔與微米之多孔三維結構可提升至 95%。研究發現，此效能提升可以歸因於結構的多孔結構所帶來的比表面積提升(564m2/g)，石墨烯良好的導電性以及表面適當的氧化基團所提供的擬電容貢獻。此外，高速充放電的性質，來自於這種特殊多階層的電極結構(微孔和奈米孔)，形成更多離子通道，提升離子擴散的能力。本研究之新穎性在於結合兩種機制，以冷凍乾燥技術處理活化後之碳材，希望能夠基於原本兩種方法的結果，更進一步提升石墨烯的儲能性能，結果得到電容值為 374F/g(增益 151%)而維持率為 95%之石墨烯電極，表示此二機制可順利結合產出新材料，並能滿足高功率元件之運作需求。;In this study, we fabricate and characterize the binder free graphene-based supercapacitor,integrated with 3D self-assemble of nanoporous graphene as a hybrid electrode by a facile approaches of activation and freeze-drying. Graphene oxide (GO) was synthesized by improved Hummer’s method, and then thermally treated at different annealing temperature in vacuum system. On the part of optimization of reducing temperature, the physical and electrochemical properties of these reduced graphene oxide (rGO) were firstly investigated, rGO reduced at 400°C gives the specific capacitance of 247 F/g, while rGO reduced at 600°C and 800°C show the same value of 115 F/g, the following discussion would be focused on rGO treated at 400°C.The as-prepared functionalized electrode exhibit a specific surface area(SSA) of up to 564 m2/g. The optimized condition allows us to yield a high specific capacitances of 374F/g which is 151% increased with respect to restacking graphene electrode.Moreover, the superior cycling stability (95% retention after 1500 times cycling) and rate capabilities, suggesting the high ion permeance and electronic conductivity of this unique and multi-functional graphene electrode. The reported approach is facile, scalable and cost-effective, which is promising for the high performance graphene-based energy storage devices.
Appears in Collections:	[Energy of Mechatronics] Electronic Thesis & Dissertation

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