Aqueous-based asymmetric supercapacitors (AASCs) provide an effective way to improve the energy density of the device by broadening the operating voltage window. In this work, nickel cobaltite (NiCo2O4) nanowires are grown homogenously on carbon fiber paper (CFP) to obtain a binder-free CFP@NiCo2O4 positive electrode through a simple hydrothermal method followed by calcination. The highly porous graphene foam (GF) as negative electrode which also exhibits self-supporting structure is prepared by a facile mild reduction process. Taking advantages of the complementary voltage window of CFP@NiCo2O4 and GF, the as-fabricated CFp@NiCo2O4//GF AASC obtains a stable working voltage window of 1.6 V, and a high energy density of 34.5 Wh kg(-1) at the power density of 547 W kg(-1), which still maintains 17.1 Wh kg(-1) at 9.68 kW kg(-1). Furthermore, it exhibits superior cycling performance with 92.2% capacitance retention rate after 10000 cycles. (C) 2014 Elsevier B.V. All rights reserved.