One-step synthesis of Ni3S2 nanoplatelets on graphene for high performance supercapacitors

Abstract

Here, we present a one-step hydrogen reduction synthesis of Ni₃S₂ nanoplatelets on graphene surface by using NiSO₄·3N₂H₄/GO as precursor. In this process, we have demonstrated that hydrazine molecule, which can coordinate with NiSO₄ in the form of pink precipitation, not only contributes to the formation of Ni₃S₂ nanoplatelets structure, but also enhances the efficiency of SO₄²⁻ to S₂⁴⁻ conversion compared with NiSO₄/GO. Supercapacitors made from the obtained Ni₃S₂/rGO composite exhibits a specific capacitance of 912.2 F g⁻¹ at 2 mV s⁻¹ scanning rate, and 875.6 F g⁻¹ at galvanostatic discharge current density of 1 A g⁻¹, along with exceptional rate capability of 83.2% at discharge current density from 1 A g⁻¹ to 10 A g⁻¹ as well as good cycling stability. We attribute the excellent performance from the improved contact between graphene and the planar Ni₃S₂ structure, which strengthens the synergistic effect with graphene as conductive support and Ni₃S₂ nanoplatelets as the pseudocapacitive materials. This method allows the direct and efficient preparation of Ni₃S₂, and provides a simple route to integrate them with graphene for energy storage applications.