Boosting Hybrid Supercapacitor Performance with Molybdate Anions-Intercalated High-Entropy-Doped LDH Nanosheets

Abstract

High-entropy doping is now a powerful strategy to optimize the electrochemical properties of nanostructured materials for advanced energy storage. Here, a binder-free 2D high-entropy doped NiCoZnCrFe layered double hydroxide intercalated with molybdate anions (NCZCFM) is reported, and synthesized via electrodeposition. The cross-linked porous nanosheet network of NCZCFM provides abundant active sites, tunable composition, improved conductivity, enlarged interlayer spacing, rapid ion kinetics, and robust structural stability. Density functional theory calculations confirm that the synergistic effects of multimetal doping and anion intercalation tailor the electronic structure, increase the density of active sites, and reduce the band gap. These features enable the NCZCFM thin-film electrode to deliver a specific capacity of 1410 C g−1 at 3 A g−1 with excellent cycling stability (93% retention after 10 000 cycles). When assembled into aqueous and flexible solid-state hybrid supercapacitors, NCZCFM delivers high energy densities of 74.5 and 67.1 Wh kg−1, respectively, along with strong rate capability and durability. These results show that high-entropy doping combined with intercalative hybridization is an effective design principle for next-generation high-energy-density cathode materials for hybrid supercapacitors.