Engineering hierarchical porous S-doped Defective nickel Cobaltite/carbon hybrids to boost efficient asymmetric electrochemical capacitor

Developing energy materials with sufficient active sites, large surface area, high conductivity, and good stability through low-cost preparation routes are vital to the promotion of energy storage technologies. However, it is not easy for the longing component-structure features converged on a single component, the hybrid strategy provides a possible approach for the thorny issue. Herein, micro/mesoporous S–NiCo₂O₄/AC with abundant vacancy defects is rationally designed via intermolecular bonding of S–NiCo₂O₄ anchored onto carbon nanosheets through a facile hydrothermal and low-temperature pyrolysis method. The constructed hybrids possess superior structural durability, good electrical conductivity, and rich active sites due to the strong interfacial conjunction and favorable synergistic effect between the porous AC and S–NiCo₂O₄. Consequently, the S–NiCo₂O₄/AC hybrid demonstrates high conductivity, reasonable specific surface area, and superior specific capacitance, and the assembled hybrid electrochemical capacitor (S–NiCo₂O₄/AC//NAC) reveals an ideal energy density of 74.8 Wh kg⁻¹ and power density of 31.4 kW kg⁻¹, which is superior to the reported devices. This work not only paves the strategy toward efficient energy materials but also provides new insight into the relationship between each phase of the hybrids.