Nanosheet@nanosheet NiZn2O4@NiZn2S4 core-shell mesoporous heterostructure as an electrode material for aqueous hybrid supercapacitors

Reasonable design of nanocomposite electrode materials with core-shell heterostructures is crucial to improve their electrochemical performance and enhance structural stability. Herein, a novel nanosheet@nanosheet NiZn2O4@NiZn2S4 (NZO@NZS) core-shell mesoporous heterostructure was synthesized on nickel foam (NF) as an electrode material for aqueous hybrid supercapacitors (HSCs). The interconnected NZS nanosheets were uniformly anchored to the vertically aligned NZO nanosheets, improving the conductivity and stability of the composite, consequently rendering the composite to exhibit excellent electrochemical performance. At a current density (Dc) of 1 A g−1, the NZO@NZS exhibits a high specific capacity (Cs) of 1516.0 C g−1. After 10,000 cycles (Dc = 15 A g−1), its capacity retention rate maintains at 86.9 %. Moreover, an HSC was assembled using the NZO@NZS as positive electrode and activated carbon as the negative electrode). At a power density (PD) of 775.0 W kg−1, the energy density (ED) is 43.4 Wh kg−1. Thus, the NZO@NZS exhibits potential as an electrode material in energy-storage devices.