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

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 Co9S8@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 Co9S8 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. A Metal‐organic framework template strategy is devised to purposefully fabricate honeycomb Co9S8@C composites with monodispersed Co9S8 nanoparticles. The Co9S8@C composites deliver a superior specific capacity, rate performance and long‐term stability. These composites are also applicable to prepare hybrid supercapacitors, which exhibit a high energy density of 58 Wh kg‐1 and an excellent power density of 17 200 W kg‐1.