A nanoperforated graphene/carbon nanotube (PG/CNT) composite is fabricated by electrostatic interaction of graphene oxide (GO) and nitrogen-doped CNTs, and subsequent catalytic carbon gasification. The nitrogen-doped sites (pyridinic N sites) of the CNTs are protonated under acidic conditions owing to the lone pair electrons, rendering the CNTs positively charged. The nitrogen-doped CNTs are uniformly incorporated into PG to form the PG/CNT composite through electrostatic attraction between the positively charged CNTs and the negatively charged GO. The resulting PG/nitrogen-doped CNT (N-CNT) composite exhibits outstanding electrochemical properties, showing high specific capacitance (288 F g-1 at 0.5 A g-1) and high rate capability (267 F g-1 at 20 A g-1) as well as excellent cycling stability (99% capacitance retention after 30 000 charge/discharge cycles). This is attributable to not only the formation of a high concentration of edge sites in PG and improvements of cross-plane ion diffusion owing to the nanoperforations, but also the enhancements in the ion-accessible area and in-plane ion diffusion due to the incorporation of N-CNT nanospacers into PG.
Bibliographical noteFunding Information:
This work was supported by the Materials and Components Technology Development Program of MOTIE/KEIT [10062226, Development of high-capacitance (0.2 F cm−2) Edge-exposed graphene electrode and high-voltage (3.5 V) polymer electrolyte for exible supercapacitor]. This research was also supported by the Energy Technology Development Project (ETDP) funded by the Ministry of Trade, Industry & Energy (20172410100150).
© 2017 The Royal Society of Chemistry.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)