Graphene has been proposed as a suitable material for electrodes in electrochemical double layer capacitors because of its excellent properties. However, a drawback is the irreversible restacking tendency of graphene during electrode preparation which, consequently, decreases the electrochemically accessible surface area. Therefore, to preserve the electrochemically accessible surface area of graphene, the development of controllable graphene structures with restacking-resistive property is highly desirable. In this work, spherical graphene with high restacking-resistive property during the re-dispersive process are synthesized using ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide as a decomposable spacer. During graphene assembly, the IL is not only used as a guide to obtain a spherical morphology, but also as a spacer that prevents restacking of graphene oxide (GO). Through our experiment, it was observed that, during the thermal treatment of spherical GO/IL to reduce GO to reduced graphene oxide (rGO), the IL could not only prevent restacking of GO sheets, but also protect its spherical morphology from the gas explosion generated by the reduction of GO. In particular, spherical rGO/IL has high surface area of 474 m2 g−1 and high restacking-resistive property such that it lost only 5% of its initial surface area after soaking in NMP, which exhibit high specific capacitance.
Bibliographical noteFunding Information:
This research was respectfully supported by Energy Technology Development Project (ETDP) funded by the Ministry of Trade, Industry & Energy, Republic of Korea ( 20172410100150 ) and by the Technology Innovation Program ( 10062226 , Development of flexible hybrid capacitor (0.25 mWh/cm 2 ) composed of graphene-based flexible electrode and gel polymer electrolyte with high electrolyte uptake) funded by the Ministry of Trade, Industry & Energy, Republic of Korea. This study was carried out with the support of ‘R&D Program for Forest Science Technology (Project No. 2017053B10-1919-BB02 )’ provided by Korea Forest Service , Republic of Korea.
All Science Journal Classification (ASJC) codes
- Materials Science(all)