Metal–Organic Framework Derived Honeycomb Co₉S₈@C Composites for High‐Performance Supercapacitors

Abstract

Abstract Unique nanostructures always lead to extraordinary electrochemical energy storage performance. Here, the authors report a new strategy for using Metal‐organic frameworks (MOFs) derived cobalt sulfide in a carbon matrix with a 3D honeycombed porous structure, resulting in a high‐performance supercapacitor with unrivalled capacity of ≈1887 F g ‐1 at the current density of 1 A g ‐1 . The honeycomb‐like structure of Co 9 S 8 @C composite is loosely adsorbed, with plentiful surface area and high conductivity, leading to improved Faradaic processes across the interface and enhanced redox reactions at active Co 9 S 8 sites. Therefore, the heterostructure‐fabricated hybrid supercapacitor, using activated carbon as the counter electrode, demonstrates a high energy density of 58 Wh kg ‐1 at the power density of 1000 W kg ‐1 . Even under an ultrahigh power density of 17 200 W kg ‐1 , its energy density maintains ≈38 Wh kg ‐1 . The hybrid supercapacitor also exhibits suitable cycling stability, with ≈90% capacity retention after 10 000 continuous cycles at the current density of 5 A g ‐1 . This work presents a practical method for using MOFs as sacrificial templates to synthesize metal‐sulfides for highly efficient electrochemical energy storage.