Core-shell structured Co3O4@NiCo2O4 electrodes grown on flexible carbon fibers with superior electrochemical properties

Rational design and synthesis of binder-free hybrid electrodes with hierarchical core-shell structures has been regarded as an effective strategy to improve the electrochemical performance of the supercapacitors. In this work, Co3O4@NiCo2O4 core-shell structures with high yield are successfully fabricated on flexible carbon cloth using a facile hydrothermal method for ultralong Co3O4 nanowires and a chemical bath for NiCo2O4 nanoflakes. The as-fabricated core-shell structures present an excellent areal capacitance of 4.35 F cm(-2) at 1 mA cm(-2) and specific capacitance of 1450 F g(-1) at 1 A g(-1) current density with a stable operational voltage of 0-0.4 V and outstanding cycling stability (similar to 4.2% loss after 6000 cycles at a charge-discharge current density of 10 mA cm(-2)). The enhanced electrochemical behaviors could be ascribed to rational design of NiCo2O4 nanoflakes adhering on Co3O4 nanowires, which promotes two electroactive materials utilizing the synergistic effect to supply more pathways for accelerating fast electron and ion transfer. The as-prepared hybrid electrode with improved supercapacitor performance could be considered as potential electrode materials for energy storage applications.