In situ ZIF-derived (Zn,co)se-N-C anchored on MXene for sodium-ion storage and hybrid supercapacitors

초록

Sodium-ion batteries (SIBs) and supercapacitors (SCs) have attracted increasing attention as viable nextgeneration energy storage systems; however, the design of efficient electrode materials continues to pose a major challenge. In this work, we report the synthesis of a novel two-dimensional (2D) composite, denoted as (Zn,Co)Se-N-C@MX-1. This material consists of N-doped C-coated cobalt selenide (CoSe2) and zinc selenide (ZnSe) nanoparticles (NPs) anchored onto MXene nanosheets (NSs), forming a synergistic architecture for enhanced electrochemical performance. The composite was prepared via the in-situ growth of ZnCo-based zeolitic imidazolate frameworks (ZnCo-ZIFs) on MXene sheets, followed by a selenization process. Electrochemical testing revealed that the (Zn,Co)Se-N-C@MX-1 electrode delivers a reversible capacity of 256.9 mAh g- 1 after 600 cycles at 1 A g- 1, along with a high-rate capacity of 187 mAh g- 1 at 5 A g- 1 in SIBs. For SC applications, it exhibited a high capacitance of 147.1 mAh g- 1 at 1 A g- 1 and maintained 98% capacity retention after 20,000 charge-discharge cycles at 2 A g- 1. Furthermore, a hybrid supercapacitor (HSC) device based on this composite achieved an energy density of 57.5 Wh kg- 1 at a power density of 726 W kg- 1, retaining 95% of its capacitance after 40,000 cycles. These results highlight the excellent structural integration and electrochemical properties of the composite, suggesting its strong potential for advanced energy storage technologies.

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