In Situ Preparation of Three-Dimensional Porous Nickel Sulfide as a Battery-Type Supercapacitor.

A one-step sulfurization method to fabricate Ni 3 S 2 nanowires (Ni 3 S 2 NWs) directly on a Ni foam (NF) was developed as a simple, low-cost synthesis method for use as a supercapacitor (SC), aimed at optimizing energy storage. Ni 3 S 2 NWs have high specific capacity and are considered a promising electrode material for SCs; however, their poor electrical conductivity and low chemical stability limit their applications. In this study, highly hierarchical three-dimensional porous Ni 3 S 2 NWs were grown directly on NF by a hydrothermal method. The feasibility of the use of Ni 3 S 2 /NF as a binder-free electrode for achieving high-performance SCs was examined. Ni 3 S 2 /NF exhibited a high specific capacity (255.3 mAh g -1 at a current density of 3 A g -1 ), good rate capability (2.9 times higher than that of the NiO/NF electrode), and competitive cycling performance (capacity retention of specific capacity of 72.17% after 5000 cycles at current density of 20 A g -1 ). Owing to its simple synthesis process and excellent performance as an electrode material for SCs, the developed multipurpose Ni 3 S 2 NWs electrode is expected to be a promising electrode for SC applications. Furthermore, the synthesis method of self-growing Ni 3 S 2 NW electrodes on 3D NF via hydrothermal reactions could potentially be applied to the fabrication of SC electrodes using a variety of other transition metal compounds.