Design and fabrication of MoO42−-intercalated LDH nanosheets coated on Co9S8 nanotubes with enhanced cycling stability for high-performance supercapacitors

Abstract

Transition metal sulfides are promising electrode materials for supercapacitors due to their excellent electrochemical performance and high conductivity. Unfortunately, the low rate performance and poor cycling stability limited their progress towards commercial applications. Herein, the core–shell structure of MoO₄²⁻-intercalated LDHs coated on Co₉S₈ nanotubes was rationally designed and prepared to improve their electrochemical performance and cycling stability by adjusting the composition of LDHs. Compared to NiMo-LDH@Co₉S₈ and CoMo-LDH@Co₉S₈, the optimized NiCoMo-LDH@Co₉S₈ electrode exhibits excellent areal specific capacitance (11 F cm⁻² at 3 mA cm⁻²) and excellent cycling stability (94.4% after 5000 cycles). In addition, asymmetric supercapacitor devices were assembled with NiCoMo-LDH@Co₉S₈ and activated carbon (AC), which delivered a high energy density of 0.94 mWh cm⁻², at a power density of 1.70 mW cm⁻², and good cycling stability (89.4% after 5000 cycles). These results indicate that the introduction of MoO₄²⁻ can enhance the synergistic effect of multiple metals and the synthesized NiCoMo-LDH@Co₉S₈ core–shell composite has great potential in the development of high-performance electrode materials for supercapacitors.