A self-standing porous carbon nanofiber (PCNF) matrix with controllable shallow hierarchical mesoporous structure on similar to 40 nm of the top layer and microporous network in the fiber bulk has been prepared by electrospinning technology coupled with Mg(NO3)(2) treatment in a one-step carbonization without further treatment. By regulating the heating rate during carbonization, PCNF with high specific surface area of 1836 m(2) g(-1) have been obtained. Symmetric supercapacitor assembled with PCNF as electrodes in 1 mol L-1 LiPF6 organic electrolyte has a specific capacity of 140 F g(-1) and an energy density of 30 Wh kg(-1) at current density of 0.1 A g(-1). And the lithium-ion capacitor (LIC) device can deliver a large energy density of 106 Wh kg(-1) (at 242 W kg(-1)), a high power density of 30 kW kg(-1) (at 53 Wh kg(-1)) and reasonably good cycling stability with capacity retention of 91% after 2000 cycles. In addition, the self-standing PCNF with high energy density and high power density presented in this work is highly desirable to apply to other electrochemical energy storage devices. (C) 2018 Elsevier Ltd. All rights reserved.