Beta-nickel hydroxide nanowires/reduced graphene oxide (RGO) composites are fabricated by a one-step reactable ionic liquid-assisted hydrothermal method, using the versatile 1-butyl-3-methylimidazolium trifluoroacetate as templates, co-solvents and reactants. The results show that beta-Ni(OH)(2) nanowires are well dispersed on the surface of reduced graphene oxide sheets, and the as-prepared beta-Ni(OH)(2) nanowires/RGO composite exhibits a huge BET surface area of 216.99 m(2) g(-1) with a pore volume of 0.34 m(3) g(-1). Furthermore, beta-Ni(OH)(2) nanowires/RGO composite as an electrode material for supercapacitors displays high specific capacitance, good cycling stability and coulombic efficiency. An extremely high specific capacitance of similar to 1875 Fg(-1) can be obtained at 1 A g(-1) in 6 M KOH aqueous solution, and retains 98.3% of its original capacity after 1000 charge-discharge cycles at 8 A g(-1). The resulting composite is a promising candidate as an electrode material for extensive applications in energy storage systems. (C) 2014 Elsevier Ltd. All rights reserved.