A high surface area N-doped holey graphene aerogel with low charge transfer resistance as high performance electrode of non-flammable thermostable supercapacitors

Abstract

The high quality carbonaceous material with high surface area and low charge transfer resistance is vital for assembling the advanced supercapacitor. Herein, a novel kind of N-doped holey graphene aerogel (NHGA) is prepared. The NHGA has high specific BET surface area of 446 m2 g−1 and low charge transfer resistance of 0.4 Ω. A large specific capacity of 318.3 F g−1 is obtained at 0.5 A g−1 in a three-electrode configuration in 6 M KOH electrolyte, indicating the high capacity characteristic. As to the NHGA based symmetrical supercapacitor, the specific capacity of 96.0 F g−1 can be achieved at 200 A g−1, presenting its robust rate property. After 10,000 cycles at 2 A g−1, the specific capacity is 262.5 F g−1 with the capacity retention of 98.4%, showing its excellent cyclic stability. Notably, the energy density of 60.3 Wh kg−1 superior to that of the related typical reported supercapacitors, is obtained at the power density of 0.9 kW kg−1 in a non-flammable ionic liquid EMIMTFSI-80 electrolyte, which is effective from 20 to 100 °C. Thus, the advanced electrochemical property of NHGA is distinctly valuable for the supercapacitor utilization especially in the extremely conditions such as fire safety and/or high temperature.