In situ morphological evolution of Ni3S2/MoS2 grow on Ni foam as binder-free electrode for hybrid supercapacitors

Binary transition metal sulfides demonstrate abundant morphological features and high redox activity. By studying the relationship between different morphological characteristics of active materials and electrochemical performance, high-performance supercapacitors can be discovered. In this work, binary Ni3S2/MoS2 composites in situ grow on the current collector Ni foam via electrochemical deposition and subsequently hydrothermal reaction, then it was directly used as a binder-free electrode for supercapacitors. The micro-morphological evolution process was investigated by controlling the hydrothermal time from 3 to 12 h. The electrochemical characterization showed that Ni3S2/MoS2@NF-9 (hydrothermal reacted for 9 h) with fluffy and abundant nanopores demonstrated the highest specific capacity (341.7 C g(-1) at 1 A g(-1)), best rate performance (50% capacity retention from 1 to 20 A g(-1)), and superior charge transfer ability compared with others. Ni3S2/MoS2@NF-9 was also used as a positive electrode to assemble Ni3S2/MoS2@NF-9//RGO hybrid supercapacitor (HSC), which displayed a specific capacity of 129.2 C g(-1) at 0.5 A g(-1) and specific energy of 26.9 Wh center dot kg(-1) at 375 W kg(-1).