Synthesis of Ni3S2 and MOF-Derived Ni(OH)2 Composite Electrode Materials on Ni Foam for High-Performance Supercapacitors

Honeycomb-like Ni(OH)2/Ni3S2/Ni foam (NF) was fabricated via a two-step hydrothermal process and subsequent alkalization. Ni3S2with a honeycombed structure was in-situ synthesized on the NF surface by a hydrothermal process. MOF-derived Ni(OH)2nanosheets were then successfully grown on the Ni3S2/NF surface by a second hydrothermal process and alkaline treatment, and a large number of nanosheets were interconnected to form a typical honeycomb-like structure with a large specific surface area and porosity. As a binder-free electrode, the prepared honeycomb-like Ni(OH)2/Ni3S2/NF exhibited a high specific capacitance (2207 F·g−1at 1 A·g−1, 1929.7 F·g−1at 5 mV·s−1) and a remarkable rate capability and cycling stability, with 62.3% of the initial value (1 A·g−1) retained at 10 A·g−1and 90.4% of the initial value (first circle at 50 mV·s−1) retained after 5000 cycles. A hybrid supercapacitor (HSC) was assembled with Ni(OH)2/Ni3S2/NF as the positive electrode and activated carbon (AC) as the negative electrode and exhibited an outstanding energy density of 24.5 Wh·kg−1at the power density of 375 W·kg−1. These encouraging results render the electrode a potential candidate for energy storage.Keywords:Ni(OH)2/Ni3S2/NF;honeycomb-like structure;two-step hydrothermal;alkalization;MOF-derived Ni(OH)2;supercapacitor