Enhanced Energy Storage Performance of 3D Hybrid Metal Sulfides via Synergistic Engineering of Architecture and Composition

Abstract

Optimizing the architecture and tailoring the phase composition are useful approaches to increasing electrochemical capacitor energy storage performance. In this work, a novel three-dimensional (3D) hybrid nickel cobalt sulfide wrapped in ultrathin carbon layer (nickel cobalt sulfides@C) was rationally designed and constructed with varied hollow and porous dendritic superstructures. The morphology evolution process has been demonstrated in detail by adjusting the Co/Ni ratio and reaction duration. Different phases of nickel cobalt sulfides@C can be tailored after sulfuration, enabling the systematic exploration of the energy storage performance with synergistic engineering of architecture and composition. Benefiting from the 3D dendritic superstructures with porous/hollow nature, tunable chemical composition, abundant phase boundaries, enhanced specific surface area, and highly conductive carbon layer matrix, (Ni,Co)9S8/NiS/Ni3S2@C yields an outstanding specific capacity of 856.6 C g–1 at the current density of 1 A g–1. Furthermore, the assembled asymmetric supercapacitor device presents higher energy density of 70.6 Wh kg–1 and power density of 8873.5 W kg–1 with excellent cycling stability. This synthetic strategy highlights the crucial role of synergistic engineering of architecture and chemical composition in practical energy storage, and the as-designed functional materials will be a competitive and promising candidate for robust electrochemical capacitor energy storage and other applications.