Copper-Cobalt-Based Sulfides: Strategy To Boost Energy Storage Performance Utilizing the Synergistic Effect of a Double Metal Ion

Abstract

The copper cobaltite chalcogenides were designed and developed via a simple and economically effective electrochemical route followed by the hydrothermal anion-exchange process without altering the morphological features. The systematic synthetic approach provided spinel crystalline-structured copper cobalt sulfide (CuCo2S4) through in situ co-deposition and copper sulfide/cobalt sulfide composite (CuS/CoS) via layer-by-layer deposition. Obtained high-resolution scanning electron microscopy explains the unique dendrite morphology of copper cobalt sulfide (CuCo2S4) with a primary midrib followed by secondary and tertiary trunks, whereas CuS/CoS governs a distinct CuS dendrite covered with thin CoS sheets homogeneously. Furthermore, the CuCo2S4 electrode material governed a superior charge storage property in supercapacitor application with a capacitive value of 966–676.8 C g–1 at a current density ranging from 10 to 40 A g–1 with a 70.15% retention value, whereas CuS/CoS delivered only 455.3–278.8 C g–1 at current densities with 61.23% retention. The promising faradaic behavior of the as-prepared material was attributed by the stable charge-discharge profile at different applied current densities as 10, 20, 30, 40, and 10 A g–1 for 5000 cycles for CuCo2S4 and CuS/CoS electrodes, respectively. To evaluate real-time charge storage behavior, an asymmetric device was assembled by coupling the CuCo2S4 electrode with activated carbon electrode using a 3 M KOH aqueous electrolyte. The fabricated device delivered 126.8 and 81.45 C g–1 at 10 and 50 A g–1, respectively. Moreover, the device demonstrated excellent cycling stability up to 5000 cycles at 50 A g–1 with 96.70% capacitive retention. Thus, the present work demonstrates the most effective strategy to exploit the synergistic effect of bimetal ions to boost the charge storage properties of a ternary chalcogenide electrode.