Fabrication of interconnected 2D/3D NiS/Ni3S4 composites for high performance supercapacitor

•NiS/Ni3S4 composites with unique interconnected 2D/3D structure were fabricated.•3D hierarchical microspheres were anchored in the interconnected 2D nanosheets.•The composites exhibited high specific capacitance and excellent rate capability.•The composites exhibited outstanding cycling stability. A novel 2D/3D NiS/Ni3S4 composite was fabricated by a one-pot hydrothermal process, in which 3D hierarchical microspheres were anchored in or covered by the interconnected 2D nanosheets. The composites exhibited a high specific capacitance of 1796 F g−1 and good capacitance retention of 80.5% at a current density of 1 A g−1 after 1000 charge-discharge cycles. Our results indicate that the interconnected 2D/3D NiS/Ni3S4 composites can be a promising electrode material for supercapacitor.