(3-Co(OH)2@CoNi2S4 core-shell heterostructures supported on carbon cloth for high-performance flexible asymmetric supercapacitors

초록

The use of core-shell heterostructures for electrode materials is widely regarded as a promising strategy for enhancing energy storage properties owing to their distinctive material and structural advantages. In this study, a (3-Co(OH)2@CoNi2S4 core-shell heterostructure was successfully synthesized and evaluated for high-performance flexible supercapacitors (SCs). The heterostructure was directly grown on nickel-coated carbon cloth (Ni-CC) via a two-step electrodeposition process, resulting in a nanosheet morphology. The resulting (3-Co(OH)2@CoNi2S4/ Ni-CC electrode exhibited outstanding electrochemical performance, attributed to the synergistic interaction between (3-Co(OH)2and CoNi2S4. It achieved a high areal capacitance of 3665.2 mF cm-2 at a current density of 2 mA cm-2 in an aqueous KOH electrolyte, retaining an excellent rate capability of 73.8 % at 10 mA cm-2. An asymmetric SC (ASC) device was assembled using (3-Co(OH)2@CoNi2S4/Ni-CC as the positive electrode and activated carbon on Ni-CC as the negative electrode. This ASC device achieved a maximum energy density of 38.07 Wh kg-1 at a power density of 272.7 W kg-1 . It exhibited outstanding cyclic stability, retaining 95.7 % of its initial capacity after 5000 cycles at 20 mA cm-2. Additionally, two serially connected ASC devices successfully powered eight red light-emitting diodes for 120 sec. These results highlight the potential of (3-Co(OH)2@CoNi2S4 core-shell heterostructures for high-performance flexible SC applications.

키워드