The graphitic petal electrodes combined with pseudocapacitive material such as MnO­­2 [1] and PANI [2] have been demonstrated to exhibit high performance with remarkable capacitance. However, these two studies utilized an aqueous electrolyte and a solid-state hygroscopic polyvinyl alcohol (PVA) electrolyte, respectively. Because graphene petals are hydrophobic, they do not wet completely with the electrolyte. Consequently, the high surface area is underutilized. The acid treatment results in brittle graphitic petals (GPs), negatively impacting the long-term durability of the device. Further, the narrow electrochemical window of the PVA/H3PO4 electrolyte leads to a relatively low cell voltage (0.8V) and thus lower power density. Room-temperature ionic liquids are promising for the fabrication of a polymer gel electrolyte due to their non-volatility, wide electrochemical window, high ionic conductivity, and improved thermal and electrochemical stabilities. Several new ion gels based on PVDF and nafion membrane separator have been studied. In the present work, we report the fabrication of all-solid-state supercapacitor with high surface area GPs and ion gel electrolyte (mixture of 1-ethyl -3 dimethyl imidazolium tetracyanoborate and PS-PEO-PS tri-block copolymer) on carbon fibers as well as woven carbon cloth. The resulting devices exhibit high performance that is comparable to the best literature reports. References [1] Xiong, G.; Hembram, K. P. S. S.; Reifenberger, R. G.; Fisher, T. S. J. Power Sources, 2013, 227, 254-259. [2] Xiong, G.; Meng, C.; Reifenberger, R. G.; Irazoqui, P. P.; Fisher, T. S. Adv. Energy Mater., 2014, 4, 1-9.

Electric double-layer supercapacitor based on 3D graphitic petals with iongel electrolyte

249th National Meeting (2015)

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