Activated graphene oxide/reduced graphene oxide electrodes and low viscous sulfonium cation based ionic liquid incorporated flexible gel polymer electrolyte for high rate supercapacitors

High rate performance of symmetrical electrical-double layer capacitors (EDLCs) constructed with activated graphene oxide (ac-GO)/activated reduced graphene oxide (ac-RGO) electrodes and ionic liquid (triethylsulfonium bis(trifluoromethylsulfonyl) imide, incorporated plastic crystal succinonitrile (SN) based flexible gel polymer electrolytes (GPE) have been reported. The 3D architecture with predominantly meso-porous character of the ac-RGO, in combination with SN-based high ion conducting GPE, renders it a high rate electrode with high value of knee frequency, f(k) (similar to 966 Hz), low response time iota(0) (similar to 20 ms) and high pulse power P-0 (similar to 111 kW kg(-1)) as compared to the ac-GO-electrode that exhibits the corresponding values: fk (similar to 215 Hz), tau(0) (similar to 60 ms) and P-0 (similar to 58 kW kg(-1)). The ac-RGO based EDLCs offer higher specific power (similar to 118 kW kg(-1)) than that for ac-GO-based EDLC (similar to 41 kW kg(-1)), as evaluated from GCD studies. However, due to the additional pseudo-capacitance arising from leftover oxygen functional groups, the ac-GO-electrodes exhibit higher values of specific capacitance and specific energy (similar to 88 -96 F g(-1) and 25 Wh kg(-1), respectively) as compared to the ac-RGO based EDLCs with specific capacitance similar to 66-72 F g(-1) and specific energy similar to 18 Wh kg(-1)). Both the EDLC cells exhibit stable capacitive performance up to similar to 11,000-13,000 GCD cycles. (C) 2016 Elsevier B.V. All rights reserved.