The in situ construction of oxygen-vacancy-rich NiCo2S4@NiMoO4/Ni2P multilevel nanoarrays for high-performance aqueous Zn-ion batteries

Abstract

The development of active and durable cathode materials is the key to achieving high-performance water-based zinc-ion batteries. In this work, NiCo₂S₄@NiMoO₄/Ni₂P nanoarrays were prepared using a hydrothermal and subsequent phosphine vapor-assisted reconstruction strategy. NiCo₂S₄@NiMoO₄/Ni₂P shows rich oxygen vacancies, which is a benefit for improving the catalytic reaction kinetics. Notably, in situ-derived Ni₂P nano-particles can increase the electrical conductivity while also acting as active sites for fast redox reactions. The unique multilevel nanoarray formed using the phosphine vapor-assisted reconstruction strategy further accelerates the mass-transfer process. Benefiting from these intrinsic properties, the NiCo₂S₄@NiMoO₄/Ni₂P electrode shows a good electrochemical performance. The NiCo₂S₄@NiMoO₄/Ni₂P materials deliver an outstanding specific capacity (258 mA h g⁻¹ at 2 A g⁻¹) and excellent rate capability (65.6% retained at 6 A g⁻¹). Moreover, the NiCo₂S₄@NiMoO₄/Ni₂P//Zn battery exhibited an outstanding specific capacity (231 mA h g⁻¹ at 1 A g⁻¹), prominent stability (122% after 5000 cycles) and a remarkable energy density of 384 W h kg⁻¹ at 0.46 kW kg⁻¹.