Hierarchical Co-Mo-Zn sulfide nanosheets for high-energy asymmetric supercapacitors

Abstract

Developing high-performance electrode materials with synergistic energy density and long-term cyclic endurance remains a formidable challenge for next-generation supercapacitors. Herein, we report hierarchical, wrinkled honeycomb-like ternary cobalt-molybdenum-zinc sulfide nanosheet networks in-situ grown on 3D nickel foam (denoted as Co₁Mo₁Zn₁-S/NF) via a two-step hydrothermal strategy. This unique ternary sulfide architecture leverages potent electronic synergistic interactions. The strategic incorporation of Zn and Mo effectively modulates the electronic structure of Co centers, lowers redox activation energy, and optimizes the d-band center, while facilitating precise electron density regulation through multi-metal charge redistribution. Significant XPS binding energy shifts confirm this robust electronic coupling, which provides abundant redox-active sites and accelerates interfacial charge transfer kinetics. Benefiting from a high electroactive surface area and the “ion-buffering reservoir” effect of mesoporous nanosheets, the Co₁Mo₁Zn₁-S/NF electrode delivers an exceptional specific capacitance of 2404 F g^− 1 at 2 A g^− 1 with 73.21% retention at 50 A g^− 1. Furthermore, the assembled asymmetric supercapacitor (Co₁Mo₁Zn₁-S/NF//AC) achieves a remarkable energy density of 95.84 Wh kg^− 1 at a power density of 750.0 W kg^− 1, outperforming most state-of-the-art binary and ternary sulfides. Notably, the device retains 78% of its initial capacitance after 10,000 cycles. This robust stability is primarily ascribed to the “lattice anchoring” effect of Zn and Mo, which mitigates structural degradation during continuous ion intercalation/deintercalation. Consequently, this study introduces a promising paradigm for the electronic and structural engineering of polymetallic sulfides for advanced energy storage.

Graphical Abstract