In situ fabrication of zeolite imidazolate framework-derived tremella-like NiCo layered double hydroxide@CoNi2S4 heterostructure for high-performance supercapacitors

Layered double hydroxides (LDHs) have garnered extensive interest for supercapacitors. However, their practical applications are hindered by low electrical conductivity, insufficient accessible electroactive sites, and proneness to agglomeration. Herein, zeolite imidazolate framework (ZIF)-derived tremella-like NiCo layered double hydroxide@CoNi 2 S 4 heterostructure (TL-NiCo LDH@CoNi 2 S 4 ) was synthesized by nickel ions etching and subsequent partial in situ sulfuration process. The tremella-like nanostructure consisted of ZIF-derived tremella-like NiCo LDH nanostructure (TL-NiCo LDH) and CoNi 2 S 4 nanoparticles. This architecture could enlarge the contact area, expose abundant electroactive sites, and provide ample channels for electron/ion transport. In addition, the nanosheets were closely interconnected and mutually supported, enhancing the structural stability. Moreover, the in situ formation of TL-NiCo LDH@CoNi 2 S 4 heterostructure can induce the electron redistribution at the heterostructure interface, boosting the electrical conductivity and reducing the adsorption energy of OH − . The optimized TL-NiCo LDH@CoNi 2 S 4 heterostructure exhibited a high capacity of 1136.0C g −1 at 1 A g −1 , excellent rate capability of 57.7% initial capacity retention at 10 A g −1 . Additionally, the electrode demonstrated superior cycling durability, retaining 87.8% of its initial capacity at 10 A g −1 over 10,000 charge-discharge cycles. Furthermore, the as-fabricated TL-NiCo LDH@CoNi 2 S 4 //activated carbon device delivered a notable energy density of 51.4 W h kg −1 when operated at 800 W kg −1 .