Bucket Effect: A Metal-Organic Framework Derived High-Performance FeS2/Fe2O3@S-rGO Negative Material for Enhanced Overall Supercapacitor Capacitance

• Key Words:ASYMMETRIC SUPERCAPACITOR; FACILE SYNTHESIS; NANOTUBE ARRAYS; ENERGY DENSITY; ADVANCED ANODE; GRAPHENE; NANOSHEETS; ELECTRODE; FE2O3; FABRICATION
• Abstract:Over the past decades, great achievements of supercapacitor positive electrode materials have been developed, but the exploration of negative electrode materials is obviously lagging and mainly focuses on low-capacity electrochemical double-layer capacitor-based carbon materials (<= 300 F g(-1), commonly), which limits the overall capacitance of supercapacitor devices for further application. In this work, using the gifted MIL-88A@GO as a precursor, we fabricate a FeS2/Fe2O3 heterostructure-coupled S-functionalized 3D rGO network (FeS2/Fe2O3@S-rGO) by a diffusion-controlled etching and vulcanizing process. The formation of heterogeneous interfaces and the strongly coupled interaction between the FeS2/Fe2O3 heterostructure and 3D S-rGO can provide high surface area for more electrochemical active sites, a rich pathway for the rapid transmission of the electron and electrolyte, and effectively alleviate the volume variation in the charging and discharging process. Therefore, the as-obtained FeS2/Fe2O3@S-rGO presents an outstanding capacity of 219.4 mA h g(-1) (790 F g(-1)) at a current density of 2 A g(-1), which is higher than that of most reported Fe-based negative materials. Then, a positive electrode of hierarchical 2D/3D Ni3S2/Co3S4 (NCS) is prepared and further fabricated with a FeS2/Fe2O3@S-rGO electrode to obtain a hybrid supercapacitor device (NCS//FeS2/Fe2O3@S-rGO), which delivers an outstanding overall capacitance value of 114.2 mA h g(-1) (274 F g(-1)) at 1 A g(-1) and provides a remarkable energy density of 85.63 Wh kg(-1) corresponding to a power density of 0.75 kW kg(-1).
• Volume:4
• Issue:10
• Translation or Not:no