Carbon nanofibers yarns (CNY) have been prepared by carbonizing twisted electrospun PAN nanofibers, which can be used as the electrode of fiber-shaped all-solid-state supercapacitor after depositing conductive polymer of polypyrrole (PPy) and reduced graphene oxide (rGO) on their surface to form a core-shell structure (CNY@PPy@rGO). The flexible and binder-free fiber supercapacitors with PVA/H3PO4 gel electrolyte have a high specific capacitance (92.57 F/g, 80.46 F/cm(3), 836.87 mF/cm(2), and 111.46 mF/cm of C-M, C-V, C-A, and C-L, respectively, at the scan rate of 2 mV/s) thanks to the core-shell structure and synergistic effects of three conponents. It also shows high cycling performance with 86% capacitance retention after 10000 cycles with excellent flexibility and stability at different bending angles. (C) 2018 Elsevier Ltd. All rights reserved.