Ultra-thin, flexible supercapacitors for portable energy storage devices and intermittent electronic applications are closer to reality. This study developed a kind of thin flexible nanofibers paper electrodes (only about 12 mm in thickness) for all-solid-state supercapacitors, which combines the features of three-dimensional porous structure from bacterial cellulose (BC) and the advantages of highly ordered conductive polymer chains from polyethylenedioxythiophene (PEDOT). The capacity and conductivity of the conductive polymer PEDOT, which was coated evenly on the surface of BC nanofibers, were exploited sufficiently. And the flexible symmetric supercapacitors device assembled with the paper electrodes demonstrated an attractive electrochemical performance (a specific volumetric capacitance of 106.3 F cm(-3) at a current density of 0.83 A cm(-3)) and an excellent cyclic stability. The electrical and mechanical properties of the devices still keep stable under various flexible conditions. So this material maybe a new choice for flexible energy-storage devices. (C) 2018 Elsevier Ltd. All rights reserved.