NiS/Ni3S2@NiWO4 nanoarrays towards all-solid-state hybrid supercapacitor with record-high energy density

The rational design and synthesis of hybrid-type electrode nanomaterials are significant for their diverse applications, including their potential 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 reported a facile and controllable synthesis of core-shell NiS/Ni3S2@ NiWO4 nanoarrays to fabricate a freestanding electrode for hybrid SCs. Impressively, the as-prepared freestanding NiS/Ni3S2@NiWO4 electrode presents an ultrahigh areal capacity of 2032 µA h cm−2 at 5 mA cm−2, and a capacity retention of 63.6% even when the current density increased up to 50 mA cm−2. Remarkably, the NiS/Ni3S2@NiWO4 nanoarray-based hybrid SC delivers a maximum energy density of 1.283 mW h cm−2 at 3.128 mW cm−2 and a maximum power density of 41.105 mW cm−2 at 0.753 mW h cm−2. Furthermore, the hybrid SC exhibits a capacity retention of 89.6% even after continuous 10,000 cycles, proving its superior stability. This study provides a facile pathway to rationally design a variety of core shell metal nanostructures for high performance energy storage devices.