High-performance MgCo2O4 nanocone arrays grown on three-dimensional nickel foams: Preparation and application as binder-free electrode for pseudo-supercapacitor

Abstract

Abstract Uniform MgCo 2 O 4 nanocone arrays (NCAs) grown radially on three-dimensional (3D) nickel foams were fabricated through a facile hydrothermal process. These MgCo 2 O 4 NCAs were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy, N 2 adsorption Brunauer-Emmett-Teller method, scanning electron microscopy and transmission electron microscopy. The MgCo 2 O 4 NCAs were directly used as a binder-free integrated electrode for electrochemical pseudocapacitors. The electrode yielded a high specific capacitance of 750 F g −1 with high cycling ability at a charge-discharge current density of 1 A g −1 (84.0% of initial specific capacitance was remained after 1000cycles) and it was much higher compared with the powder MgCo 2 O 4 (320 F g −1 at 0.5 A g −1 ). Evidently, MgCo 2 O 4 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 MgCo 2 O 4 nanocone with highly-conductive origin nickel foam, as well as the enlarged specific surface area (335.8 m 2 g -1 ). This study approves the future applications of the MgCo 2 O 4 NCAs inspired large-scale supercapacitor grown on low-cost nickel foams.