Electrochemical properties of Ni3S2@MoS2-rGO ternary nanocomposite as a promising cathode for Ni–Zn batteries and catalyst towards hydrogen evolution reaction

Abstract

The development of active and stable materials has great importance for the commercialization of nickel-zinc (Ni–Zn) batteries and hydrogen production. Transition metal sulfides have good theoretical properties for these applications. In this research, we present the synthesis and characterization of Ni3S2@MoS2 nanocatalyst and its hybrid with reduced graphene oxide (Ni3S2@MoS2-rGO). The capability of these materials is investigated as cathode material for Ni–Zn batteries and hydrogen evolution in alkaline media. In the case of Ni–Zn batteries, the assembled Ni3S2@MoS2-rGO//Zn battery shows a discharge capacity of 249.3 mAh g−1 with coulombic efficiency of 97.2%, showing a higher electrochemical capacity than Ni3S2//Zn battery. Besides, this sample presents the high-capacity retentions of 87% with coulombic efficiency of around 98% during 1000 cycles. These results benefit from the features of substantially improved electrical conductivity, good intrinsic capacity, and good electrical interaction between Ni3S2 and MoS2 to accommodate a large number of hydroxyl anions. Besides, for the hydrogen evolution reaction, the Ni3S2@MoS2-rGO electrocatalyst shows an overpotential of 94 mV at 10 mA/cm2 with a Tafel slope of 41 mV/dec and stability of 89% after 1000 LSV cycles, which is higher than other prepared materials. The unique morphology and abundant active sites enhance the HER performance of the electrocatalyst. The results demonstrated that the Ni3S2@MoS2-rGO cathode prepared during the facile synthesis possesses a good potential and capabilities as a cathode electrode for rechargeable Ni–Zn batteries and also a catalyst for hydrogen evolution.