Novel Mo-doped nickel sulfide thin sheets decorated with Ni–Co layered double hydroxide sheets as an advanced electrode for aqueous asymmetric super-capacitor battery

Rational design and fabrication of composite electrode materials via heteroatom doping and integrating with other components are of significance to improve their energy storage capacity. Herein, the Mo- introduced nickel sulfide thin sheets decorated with Ni–Co Layered Double Hydroxide sheets (Mo–NiS2@NiCo-LDH) grown directly on Ni foam were successfully constructed thought multistep hydrothermal method. The well-designed 2D/2D coupling structure, with interconnected thin sheets, can provide abundant uniform mesoporous structure to facilitate the electrolyte penetration and more redox active sites during energy storage process. The resulting Mo–NiS2 electrode possesses a high capacity of 207.9 mAh g−1 (1663.2 F g−1) at 1 A g−1. After integrating with NiCo-LDH, the Mo–NiS2@NiCo-LDH electrode exhibits a high capacity of 325.6 mAh g−1 (2604.8 F g−1) at 1 A g−1. Furthermore, the assembled asymmetric supercapacitor (Mo–NiS2@NiCo-LDH//AC) achieving high energy density of 38.1 W h kg−1 at a power density of 800.0 W kg−1, showing excellent cycling performance. And the fabricated aqueous Ni–Zn battery (Mo–NiS2@NiCo-LDH//Zn) shows a high capacity of 274.9 mAh g−1 at 1 A g−1 and exhibits a reversible capacity of 182.3 mAh g−1 after 700 cycles at 4 A g−1. The excellent electrochemical performance of Mo–NiS2@NiCo-LDH arises from the synergistic contributions from Mo-introduced nickel sulfide thin sheets and Ni–Co Layered Double Hydroxide nanosheets.