One-Pot Hydrothermal-Derived NiS 2 -CoMo 2 S 4 with Vertically Aligned Nanorods as a Binder-Free Electrode for Coin-Cell-Type Hybrid Supercapacitor.

Transition bimetallic sulfides are exploited as high-capacity electrode materials in energy storage devices owing to their abundant electroactive sites and relatively high electrical conductivity compared with metal oxides. Here, an in situ conversion of metal ions into NiS 2 -CoMo 2 S 4 vertically aligned nanorod arrays on nickel foam (NS-CMS NRAs@NF) using a one-step hydrothermal technique to address the "dead-mass" limitation and multi-step preparation methods is reported. An in situ-converted NS-CMS NRAs obtained for 12 h of reaction time (NS-CMS NRAs-12 h@NF) delivers a superior areal capacity of 780 μAh cm -2 to the other NS-CMS electrodes synthesized for 6 h (543.1 μAh cm -2 ) and 18 h (636.7 μAh cm -2 ) at 7 mA cm -2 . A coin-cell-type hybrid supercapacitor (HSC) is also fabricated to unveil the practical adaptability of NS-CMS NRAs-12 h@NF electrode. Utilizing its structural and active material intriguing features, assembled coin-cell-type HSC achieves a high areal capacitance of 246.2 mF cm -2 (5 mA cm -2 ) along with maximum areal energy density (147 μWh cm -2 ) and power density (21.3 mW cm -2 ), respectively. Furthermore, the capability of coin-cell-type HSC in real-time applications is also inspected. This work promotes in situ deposition strategy to fabricate metal sulfide-based nanostructures for high-performance electrochemical capacitors.