Hierarchical carbon nanofiber-based NiCo2S4/NiCo-LDH/C nanostructure array with efficient charge transfer for flexible solid-state supercapacitors

Layered double hydroxides (LDHs) hold great promise for flexible solid-state supercapacitors owing to their high theoretical capacitance and distinctive architecture. However, their proneness to agglomeration and poor electrical conductivity have long hindered the manifestation of outstanding electrochemical performance. In a groundbreaking approach, we have engineered a hierarchical carbon nanofiber-based NiCo₂S₄/NiCo-LDH/C nanostructure array. The meticulously crafted hierarchical structure not only imparts remarkable stability to the electrode but also ingeniously harnesses the synergistic interplay among materials. Through density functional theory calculations, we have precisely identified and verified the active sites for charge transfer, unveiling a new understanding of the underlying mechanisms. This unique structure significantly facilitates ion transfer in the vicinity of NiCo-LDH, substantially elevates electrical conductivity, and notably increases the adsorption capacity of OH⁻. Moreover, it gives a substantial boost to the quantum capacitance. As a result, the electrode showcases a high specific capacitance of 1838.3 F/g. This research pioneers an effective and versatile strategy that can be readily applied to the majority of LDHs, opening up new avenues for enhancing their efficiency of supercapacitor materials.