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 mor-phology, 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 nano-composite 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.(c) 2023 Elsevier B.V. All rights reserved.