Design and fabrication of MoO 4 2- -intercalated LDH nanosheets coated on Co 9 S 8 nanotubes with enhanced cycling stability for high-performance supercapacitors.

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 MoO4 2- -intercalated LDHs coated on Co9 S8 nanotubes was rationally designed and prepared to improve their electrochemical performance and cycling stability by adjusting the composition of LDHs. Compared to NiMo-LDH@Co9 S8 and CoMo-LDH@Co9 S8 , the optimized NiCoMo-LDH@Co9 S8 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@Co9 S8 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 MoO4 2- can enhance the synergistic effect of multiple metals and the synthesized NiCoMo-LDH@Co9 S8 core-shell composite has great potential in the development of high-performance electrode materials for supercapacitors.