3D (Three-dimensional) sandwich-structured of ZnO (zinc oxide)/rGO (reduced graphene oxide)/ZnO for high performance supercapacitors

3D (Three-dimensional) ZnO (zinc oxide)/rGO (reduced graphene oxide)/ZnO sandwich-structured were synthesized by adding zinc oxide powder to the reaction of graphitic oxide reduction and heating. In this reaction, ZnO nanorods arrays with the size of 20–40 nm grew on both surfaces of rGO sheets directly. Compared with the rGO, the as-obtained ZnO/rGO/ZnO exhibited higher surface area. The electrochemical performance of ZnO/rGO/ZnO electrodes was investigated for energy storage. The maximum specific capacitance of 275 F g−1 at scan rate of 5 mV s−1 by chronopotentiometry was achieved for ZnO/rGO/ZnO sandwich-structured in 1.0 M Na2SO4. The hybrid ZnO/rGO/ZnO sandwich-structured exhibited an excellent rate capability and excellent long-term cycling stability as compared with rGO. Such results demonstrated that this ZnO/rGO/ZnO sandwich-structured was a promising candidate of electrode material for high-performance supercapacitor.