In-situ solid-state transformation of MOF-derived hierarchical CoxNi1-xS2 microspheres for high-performance supercapacitors

In order to break the impasse of limited energy storage capacity in supercapacitors, it is essential to develop advanced electrode materials. In this work, a method for the construction of hierarchical Co x Ni 1-x S 2 microspheres based on MOF template derivatization strategy is proposed, with morphology control achieved through an in-situ solid-state sulfurization reaction. NiCo-LDH (NiCo layered double hydroxides) nanosheets were evenly grown on the surface of CoBTC (cobalt-benzene tricarboxylic acid based MOF) as a sacrificial template, and then sulfided to form Ni-Co sulfides with porous wrinkle structure, which effectively promoted the swift transfer of ions and electrons. Moreover, both of vulcanization temperature and sulfur source content were further systematically controlled to optimize the structure design and enhance electrochemical efficiency of the electrode materials. The as-prepared composites exhibit excellent specific capacitance (1 A·g −1 at 1243.69 F·g −1 ), along with reliable cycle stability, maintaining 90 % capacity after 1000 cycles, benefit from the synergistic effect between nickel and cobalt and the construction advantages of MOF-derived framework structures. The assembled ASC (asymmetric supercapacitor cell) device demonstrates an energy density of 38.19 Wh·kg −1 at a power density of 800 W·kg −1 and a cycle stability of 88 % after 1000 cycles. This approach offers a practical and efficient route to developing high-performance bimetallic sulfide electrode materials on a scalable level, demonstrating promising potential for widespread use in future energy storage technologies.