An integrated porous Ni3S2 electrode assisted by copper with advanced performance for sodium storage

•Coupled with Cu particles planted on the surface of Ni foam, an integrated porous Ni3S2 electrode (NCNS) was synthesized for sodium storage via a simple hydrothermal process.•NCNS showed an advanced electrochemical performance and long life-span for sodium storage under a fast kinetics controlled by capacitance.•An idea of electrode strengthening is proposed, which can improve the stability and life-span of electrode without affecting the main reaction.