Advanced battery-supercapacitor hybrid device based on Co/Ni-ZIFs-derived NiCo2S4 ultrathin nanosheets electrode with high performance

Battery-supercapacitor hybrid device (BSH) consisted of a battery-type electrode and a capacitor-type electrode is a promising candidate for both high energy and power density energy storage systems. In an effort to design a high-performance battery-type electrode of BSH, we propose a facile and artful two-step strategy to obtain NiCo2S4 ultrathin nanosheets by utilizing bimetallic Co/Ni-ZIFs as a precursor. NiCo2S4 nanosheets are directly grown on nickel foam via this method, which involves the growth of Co/Ni-ZIFs and the morphology of Co-Ni-S/NF transforms into ultrathin nanosheets through a simple sulfuration procedure. The as-prepared Co1Ni1-S/NF electrode achieves a high specific capacity of 301.1 mAh g−1 at 2 A g−1, which benefits from the synergistic interplay between Co and Ni ions and the unique 3D nanoarchitectures constructed by 2D ultrathin nanosheets. Moreover, Co1Ni1-S/NF and activated carbon/NF are chosen for fabricating a battery-supercapacitor hybrid device. The assembled Co1Ni1-S/NF//AC/NF BSH exhibits a large energy density of 48.65 W h kg−1 at a power density of 8.51 kW kg−1, a specific capacity of 80.56 mAh g−1 at 1 A g−1 and a remarkable stability over 5000 cycles at 5 A g−1. The encouraging results could provide new insights for energy storage systems.