Facile synthesis of nanostructured sodium and MoS2 incorporated Ni-MOFs with excellent cyclic durability for symmetric supercapacitor application

Abstract

Highly porous and nanostructured metal-organic frameworks (MOFs) have fascinated enormous interest as electrode active materials for electrochemical energy storage systems, whereas their practical applications are significantly hindered by their relative inferior energy density and cyclability. In this study, MoS2 with layered structure was successfully incorporated onto hierarchical Ni-MOFs via a facile hydrothermal approach. Moreover, sodium cations were introduced to improve electronic conductivity. The resulting nanocomposites (sodium ions and MoS2 incorporated Ni-MOFs) exhibited hierarchical porous structures with varying dimensions, offering increased volume for charge storage and diffusion channels for electrolyte ions. Benefiting from the unique topological architectures, the as-synthesized porous nanocomposites delivered an excellent supercapacitive performance, achieving a superlative energy of 33.33 Wh kg−1 and a power density of 3390 W kg−1. Furthermore, the as-fabricated symmetric supercapacitor device delivered a remarkable cycling durability where the acquired outstanding capacitance retention was 97.42% and coulombic efficiency was 97.82% respectively over more than 10,000 cycles in an aqueous electrolyte.