Hierarchical urchin-like Co9S8@Ni(OH)2 heterostructures with superior electrochemical performance for hybrid supercapacitors

Abstract

The hierarchical core–shell heterostructure is a promising electrode material for the construction of high-performance hybrid supercapacitors. Here, a novel urchin-like Co₉S₈@Ni(OH)₂ core–shell heterostructure was synthesized. The Co₉S₈@Ni(OH)₂ heterostructure exhibited high specific capacity of 1307 C g⁻¹ at a current density of 1 A g⁻¹ and good cycling stability with 98.6% retention after 5000 cycles. Moreover, the hybrid supercapacitor fabricated by using the Co₉S₈@Ni(OH)₂ heterostructure as the cathode and activated carbon as the anode delivered maximum energy density of 48 W h kg⁻¹ at 800 W kg⁻¹ with good cycling stability of 85% after 6000 cycles. The unique hierarchical heterostructure and the synergistic effect between each component contributed to the remarkable electrochemical performance of the Co₉S₈@Ni(OH)₂ heterostructure. These results will encourage researchers to construct high-performance hybrid supercapacitors by using core–shell heterostructure electrode materials.