Mesoporous carbon nanofibers (MCNFs) were prepared by electrospinning, carbonization and pickling process using phenolic resin as carbon source, pluronic F127 and Mg(NO3)(2)center dot 6H(2)O as dual template. The obtained samples contained numerous oriented and parallel-to-fiber-axised mesopores and presented a specific surface area of 674 m(2) g(-1) as well as high mesoporosity of 95%. The MCNFs were directly cut into electrodes free of binder for supercapacitors and tested in 6 M KOH electrolyte. In three-electrode system, the MCNFs showed a high specific capacitance (270 F g(-1) at 0.2 A g(-1)) and outstanding rate performance (186 F g(-1) at 20 A g(-1)). In two-electrode cell, the MCNFs presented a high capacitance of 160 F g(-1) (86% of value at 0.1 A g(-1)) and excellent cycling stability (95% of capacitance retention after 5000 cycles). The free-standing nature and outstanding capacitance made the MCNFs a good candidate as electrode materials for next-generation flexible supercapacitors. (C) 2016 Elsevier B.V. All rights reserved.