Mesoporous Hybrid NiCo2O4/CeO2 Hierarchical Hollow Spheres for Enhanced Supercapacitors

Abstract Hollow architecture electrode materials, which are regarded as desired candidates for supercapacitors, possess large specific surface area, porous structure and inner cavities. In the current work, nanosheet assembled mesoporous hybrid NiCo2O4/CeO2 hierarchical hollow spheres are first successfully synthesized by a facile self‐template method, which includes the preparation of hierarchical hollow sphere precursors as the template by a solvothermal method and then calcinations in air. The hybrid NiCo 2 O 4 /CeO 2 hierarchical hollow spheres exhibit specific surface area of 136.3 m 2 g −1 . As an electrode material, it exhibits a large specific capacitance of 2781.3 F g −1 at 8.0 A g −1 and excellent cycling stability (approximately 3% loss after 5,000 charging‐discharging cycles) in 3.0 M KOH + 0.10 M K 4 [Fe(CN) 6 ] electrolyte. Furthermore, an asymmetric supercapacitor device is assembled with the mesoporous hybrid NiCo 2 O 4 /CeO 2 hierarchical hollow spheres and activated carbon. The fabricated device exhibits an energy density of 59.1 Wh kg −1 at a power density of 3298.7 W kg −1 . When the power density reaches 8243.6 W kg −1 , the energy density remains as high as 44.2 Wh kg −1 . Such notable electrochemical properties illustrate that mesoporous hybrid NiCo 2 O 4 /CeO 2 hierarchical hollow spheres are ideal electrode materials for supercapacitors.