Development of Ultrathin Two-Dimensional Cobalt-Based Metal–Organic Framework Nanosheets for High-Performance Supercapacitors

Abstract

Recently, ultrathin two-dimensional (2D) MOF nanosheets with unique and superior dimension-related characteristics, inclusive of high surface areas, abundantly accessible active metal centers, and excellent electrical conductivity, have drawn intensive interest in a broad spectrum of functional electrochemical devices like rechargeable batteries and supercapacitors. Herein, we synthesized ultrathin 2D Co-MeIM (MeIM = 2-methylimidazole) through a facile one-pot hydrothermal approach with a thickness of about 1.5 nm. The prepared ultrathin 2D Co-MeIM nanosheet possesses highly exposed active cobalt sites, less charge transfer resistance, and quicker ionic transfer, enabling it to play a significant role as a propitious electrode candidate for outstanding execution supercapacitors. Notably, the ultrathin 2D Co- MeIM nanosheet displayed an elevated capacitance of 1589 F g−1 at a constant current of 0.6 A g−1, and it retained 91.6% of its specific capacitance after 4000 cycles, revealing superb long-term cycling performance.