Hierarchical nanocomposite that coupled nitrogen-doped graphene with aligned PANI cores arrays for high-performance supercapacitor

Nitrogen-doped graphene coupled with aligned polyaniline cores arrays (NG/PANI) has been successfully prepared by in-situ dilution polymerization. The polyaniline core arrays in situ grows on nitrogen-doped graphene nanosheets to form hierarchical NG/PANI hybrid nanosheets. Electrochemical measurements show that NG/PANI nanocomposite electrode exhibits outstanding electrochemical performance compared with individual electrode. Especially, the as-prepared NG/PANI-35% electrode exhibits the highest specific capacitance of 620 F g(-1) at 0.5 A g(-1) (with 76% capacitance retention as the current density increased 20-folds) and keeps high capacitance retention of 87.4% at 5 A g(-1) after 5000 charge-discharge cycles, which due to nitrogen doping and synergistic effect between hierarchical nitrogen-doped graphene nanosheets and aligned polyaniline cores arrays. The asymmetric supercapacitor on the basis of NG/PANI nanocomposite and actived carbon (AC) delivers a superior energy density of 31.14 W h kg(-1) at 800 W kg(-1). The splendid electrochemical properties are attributed to PANI cores arrays in situ growth on the surface of nitrogen-doped graphene nanosheets, which can shorten the path of ions diffusion and charge transport, protect the structure of composites effectively, and avoid the volume change of polyaniline during the charging and discharging process. Therefore, well-designed hierarchical NG/PANI nanocomposite could be a promising candidate for high-performance supercapacitors. (C) 2019 Elsevier Ltd. All rights reserved.