Regulated synthesis of Eutectic Ni3S2/NiS nanorods for quasi-solid-state hybrid supercapacitors with high energy density

Abstract The rational design and synthesis of hybrid-type electrode nanomaterials are of significant importance for their diverse applications, including their promising usage as high-efficiency nanoarchitectures for supercapacitors (SCs) as a class of promising energy-storage systems for powering next-generation electric vehicles and electronic devices. Here, we report a regulated synthesis of eutectic structured Ni3S2/NiS nanorods, which is demonstrated to have fantastic electrochemical performance as a freestanding electrode for hybrid SCs. The as-prepared Ni3S2/NiS significantly increases the interfacial atomic activity between Ni3S2 and NiS, which provides more electrochemical active sites and facilitates fast ion diffusion. The Ni3S2/NiS electrode presented superior areal specific capacity of 1330 μA h cm−2 and remains 67.1% of its initial capacity when the current density increased 20 folds. The as-assembled hybrid supercapacitor demonstrated fantastic energy density of 0.567 mWh cm−2@4.251 mW cm−2, and retained at 0.476 mWh cm−2@34.440 mW cm−2 with long durability. This study provides a facile pathway to rationally design a variety of eutectic structured metal compounds for high performance energy storage devices.