[en] Highlights: • Co₃O₄@NiCo₂O₄ core-shell structures with high yield are successfully fabricated on flexible carbon cloth. • The as-prepared heterostructures are directly functionalized as the supercapacitors (SCs). • The SCs demonstrate high areal capacitance and excellent cyclic performance after 6000 cycles. 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 (~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.