Rechargeable energy storage systems with merits of durable, powerful, and inexpensive are urgently desired along with the rapid development in portable electronics and electric vehicles. Herein, a facile electrochemical method is employed to prepare a free-standing exfoliated graphite (EG) electrode with significantly enhanced surface area and pore volume. Then a binder-free composite electrode is fabricated by a double-phase (DP) electrochemical deposition of vertical arrays of Ni(OH)2 throughout the EG hydrogel electrode in an organic electrolyte. The obtained composite, Ni(OH)2@EG-DP, exhibits battery-type capacitive behavior and much higher capacity than its counterparts fabricated either by single-phase electrochemical deposition or with non-exfoliated graphite foil. Ni(OH)2@EG-DP also exhibits remarkable rate capability and cycling stability, due to the well-dispersed ultrathin Ni(OH)2 nanoplatelets and the graphene-like expanded gallery of EG, enabling the efficient transportation of both electrons and ions. When coupling with an active carbon anode, the assembled asymmetric supercapacitor shows 84.5% capacity retention after 20000 cycles at 8 A g−1, and a high energy density of 34.7 Wh kg−1 at the power density of 15 kW kg−1. This work opens an avenue towards the efficient construction of free-standing three-dimensional (3D) conductive substrates and high-performance 3D hybrid electrodes using electrochemistry.