In this work, we demonstrate a facile and universal approach to fabricate the ACNF/PANI/NiO ternary composite as electrode materials for supercapacitors through the combination of electrostatic spinning, carbonization and in-situ polymerization methods. By utilizing electrospun NiO-incorperated PAN-based activated carbon nanofibers (ACNF) as carbon-based template, compact three-dimensional (3D) conductive nanofiber network structures are constructed with PANI nanoparticles densely coated on the activated carbon nanofibers, contribute to enhancing electrical conductivity and rapid electron transport during the charge-discharge processes. The deposited PANI in the ACNF/PANI/NiO composite all possesses well-organized uniformity on the NiO incorperated ACNF, producing myriads of open, hierarchical inflorescence-like nanoflakes, which not only increase the specific surface area of the composite but also promote the surface redox reaction of electrode and electrolyte solution. As a consequence, the ACNF/PANI/NiO-03 composite exhibits a high specific capacitance of 1157 F.g(-1) at 1 A.g(-1), and it still maintains 720 F.g(-1) at a high loading current density of 10 A.g(-1). Besides, the ACNF/PANI/NiO-03 composite retains 93.89% of the original capacity after 5000 continuous charge-discharge cycles at 10 A.g(-1), exhibiting outstanding cycle stability. In addition, an asymmetric supercapacitor fabricated with ACNF/PANI/NiO-0.3 composite demonstrated excellent energy density of 20.14 Wh.kg(-1) at a power density of 102.67 W.kg(-1). (C) 2017 Elsevier B.V. All rights reserved.