A Ni₃S₂ nanorods/Ni foam composite electrode is prepared as a high-performance catalyst for the oxygen evolution reaction (OER), which exhibits excellent OER activity with a small overpotential of ∼157 mV based on the onset of catalytic current.

In this review, the recent progress on the preparation of hybrid micro-/nano-structures derived from metal–organic frameworks and their applications in energy storage and conversion is systematically summarized.

Three-dimensional (3D) graphene materials (3DGMs) are of great importance due to their unique properties and practical applications. A number of 3DGMs with novel structures have been developed in recent years. This review presents the current progress of 3DGMs. After introducing the preparation strategies of 3DGMs, we summarize the reported 3DGMs based on their different structures, and then focus on the description of their preparation methods, properties and applications. Lastly, the applications of 3D graphene-based materials in supercapacitors are described.

A three-dimensional graphene network (3DGN) grown on nickel foam is an excellent template for the synthesis of graphene-based composite electrodes for use in supercapacitors. Ni(OH)₂ nanosheets coated onto single-crystal Ni₃S₂ nanorods grown on the surface of the 3DGN (referred to as the Ni₃S₂@Ni(OH)₂/3DGN) are synthesized using a one-step hydrothermal reaction. SEM, TEM, XRD and Raman spectroscopy are used to investigate the morphological and structural evolution of the Ni₃S₂@Ni(OH)₂/3DGN. Detailed electrochemical characterization shows that the Ni₃S₂@Ni(OH)₂/3DGN exhibits high specific capacitance (1277 F g⁻¹ at 2 mV s⁻¹ and 1037.5 F g⁻¹ at 5.1 A g⁻¹) and areal capacitance (4.7 F cm⁻² at 2 mV s⁻¹ and 3.85 F cm⁻² at 19.1 mA cm⁻²) with good cycling performance (99.1% capacitance retention after 2000 cycles).