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 approximate to 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 approximate to 38 Wh kg(-1). The hybrid supercapacitor also exhibits suitable cycling stability, with approximate to 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.