Both MOFs-derived Fe-Co-Ni ternary hydroxide positive and Fe2O3/reduced graphene oxide negative electrode for asymmetric supercapacitors

Abstract

To design and construct high-performance asymmetric supercapacitors (ASC), we use the same Fe-based metal-organic framework (MIL-88A) as the precursor for the first time to prepare iron-cobalt-nickel ternary metal hydroxides (Fe-Co-Ni-OH) and Fe2O3 compounded with reduced graphene oxide (Fe2O3/RGO-1). As a positive electrode, Fe-Co-Ni-OH has a specific capacitance of 1065 F g−1 at 1 A g−1 and exhibits excellent rate performance and cycle stability due to its unique spindle-like structure of the surface growth nanosheets and the synergistic effect between the three metals. The introduction of RGO effectively connects the independent spindle-like Fe2O3 and enhances the conductivity and structural stability of the material. So that the Fe2O3/RGO-1 negative electrode has a specific capacitance of 734 F g−1 at 1 A g−1, and its cycle stability is significantly improved compared with the single Fe2O3 (increasing from 64 % to 85 %). The constructed Fe-Co-Ni-OH//Fe2O3/RGO-1 ASC possesses a satisfactory energy density of 43.11 Wh kg−1 at a power density of 800 W kg−1, which is superior to parts constructed with similar material compositions in the same period. This research provides a new perspective for developing high-performance, low-cost, and environmentally friendly green energy storage devices.