Porous corallite-like NiSe2/CNTs nanocomposite fabricated by a convenient one-step in-suit solid-phase synthesis method with high performance in both supercapacitor and sodium-ion battery

If the agglomeration problem can be well addressed, the solid-phase synthesis method would be evolved into an effective strategy for the preparation of transition metal-base energy storage materials with the merits of convenience, eco-friendliness, and cost-effectiveness. In this work, a convenient one-step in-suit solid-phase synthesis (ISPS) method is developed for the fabrication of a porous corallite-like NiSe2/CNTs nanocomposite. The porous 3D framework constructed by CNTs provides a high-conductivity substance for the loading of NiSe2 nanospheres to form a nanocomposite with high conductivity, loose porous morphology, and small NiSe2 size, resulting in a good performance in both supercapacitor (SC) and sodium-ion battery (SIB). A high specific capacity of 172.70 mAh g−1 is achieved at 1 A g−1 for the synthesized nanocomposite as an electrode material of SC, which value remains at 108.64 mAh g−1 at 20 A g−1. High specific energy (42.8 Wh kg−1 at 0.84 kW kg−1) and excellent cycle durability (100% capacity retention after 20,000 cycles) are exhibited by a hybrid supercapacitor device assembled with a hierarchical porous carbon. When used as the anode of SIB, the synthesized nanocomposite delivers a high reversible specific capacity of 415.8 mAh g−1 after 270 cycles at 100 mA g−1, which is retained at 330 mAh g−1 after 360 cycles at 2.0 A g−1. The outstanding performance of the synthesized nanocomposite in both SC and SIB demonstrates the great prospect of the proposed ISPS method in the synthesis of high-performance energy storage materials. [Display omitted] •Developing an in-suit solid-phase method for the synthesis of NiSe2/CNTs nanocomposite.•NiSe2 nanospheres are in-suit synthesized and decorated on CNTs.•Good performance is exhibited in both supercapacitor and sodium-ion battery applications.