Uniform MgCo2O4 nanocone arrays (NCAs) grown radially on three-dimensional (3D) nickel foams were
fabricated through a facile hydrothermal process. These MgCo2O4 NCAs were characterized by X-ray
diffractometry, X-ray photoelectron spectroscopy, N2 adsorption Brunauer-Emmett-Teller method,
scanning electron microscopy and transmission electron microscopy. The MgCo2O4 NCAs were directly
used as a binder-free integrated electrode for electrochemical pseudocapacitors. The electrode yielded a
high specific capacitance of 750 F g1 with high cycling ability at a charge-discharge current density of
1 A g1 (84.0% of initial specific capacitance was remained after 1000cycles) and it was much higher
compared with the powder MgCo2O4 (320 F g1 at 0.5 A g1). Evidently, MgCo2O4 NCAs achieved
excellent electrochemical performance owing to the unique 3D nickel-foam-based in-situ self-assembly,
which accelerated electron transport and diffusion as well as intimate electrode/electrolyte contact. The
remarkable performance of the aqueous symmetric supercapacitor device without addition of binders or
conductive additive is attributed to the close-knit combination of MgCo2O4 nanocone with highlyconductive
origin nickel foam, as well as the enlarged specific surface area (335.8 m2 g-1). This study
approves the future applications of the MgCo2O4 NCAs inspired large-scale supercapacitor grown on lowcost
nickel foams.