目前超高電容電極材料多以石墨烯方向發展，但製程皆過於繁複，本研究期望利用簡便的電化學電解的方法，利用不同電解電流製造不同石墨烯并探討其對於超高電容電化學性質之影響。本研究選用三種不同電解電流下之石墨烯在離子液體BMP-DCA中進行比較，分別是3 A電流下電解之石墨烯 (3 A)、4.5 A電流下電解之石墨烯 (4.5 A)以及6 A電流下電解之石墨烯 (6 A)，根據結果顯示，3 A石墨烯的比電容值高於其他兩者，並且擁有高的比電容值 (198 F/g)、能量密度 (74.9 Wh/kg)以及高的功率密度 (18.6 kW/kg)，五百圈後維持率仍有86 %。目前超高電容普遍是以rGO在為主軸，本研究比較高溫熱還原之石墨烯以及電化學電解石墨烯在離子液體BMP-DCA的超高電容行為，由結果得知電化學電解石墨烯在離子液體BMP-DCA中有較好的超高電容性能。
本研究嘗試通過摻雜硼原子來對電化學石墨烯進行改質，透過對電化學石墨烯與硼酸之高溫燒結，可以得到最高硼含量為7.5%之石墨烯，因而作為電極材料應用于超高電容中，其中可以得到可以得到最佳硼摻雜條件為硼酸與石墨烯質量比為3:7時，其擁有最高的比能量密度46.9 Wh/kg，以及比功率密度8.6 kW/kg，五百圈後維持率為183%。
The graphene sheets were prepared by Electrochemical Exfoliation method in this study, and were used for the electrode in supercapacitor. We chose ionic liquids as electrolyte for their wide potential window to get better energy density and power density.
Currently, most of supercapacitor electrodes are graphene sheets, but the processes are too complicated, so this study expects to use a simple electrochemical method to get graphene. We choose different electrolytic currents to manufacture different kind of graphene and then discuss the influences of the electrochemical properties in supercapacitor. In our study, three different electrolysis currents of graphene are choosen to be compared in the ionic liquid BMP-DCA. According to the results, it showed that the current of 3A graphene has a specific capacitance which is higher than the other two. The 3A graphene has a high specific capacitance (198 F / g), which gets better energy density for 74.9 Wh/kg and power density for 18.6 kW/kg, and the retention after five hundred cycles is still 86%. In general, the main manufacture of capacitors electrode is reduced graphene oxide (rGO). So in this study, we also compare the behaviors of the rGO which use the thermal reduction and the electrochemical exfoliation graphene in ionic liquids BMP-DCA. From the results, it shows that the electrochemical exfoliation graphene has the better performance in BMPDCA.
In our study, we attempt to make the electrochemical graphene modified by doping boron atoms through mixing the graphene and boric acid in boiler tube. Then we can get the graphene which the content of boron can be up to 7.5%, and thus use it in supercapacitors as electrode, When the mass ratio of boric acid and graphene is 3:7, we obtain the optimum conditions, which has the highest energy density of 46.9 Wh/kg, and a specific power density of 8.6 kW/kg, and 183% retention after five hundreds cycle.
Key Word: Supercapacitor, Ionic liquid, Graphene, Electrochemical exfoliation, Boron-doping.