The cold plasma synthesis of hierarchical MOF-based nanocomposites with improved electrochemical properties for energy storage devices

Metal-organic frameworks (MOFs) have become known as an attractive group of materials for energy storage applications because of their spectacular characteristics, like porous properties, tunable chemical compositions, and adaptable geometry morphologies. Herein, we produce hierarchical nanostructures based on MOF-71 by using a straightforward one-pot cold plasma method to prepare a high-performance dual Ni/Co-MOF-reduced graphene oxide (Ni/Co-MOF@rGO) material as a supercapacitor electrode. Interestingly, the as-synthesized nanostructure displays a special morphology with superior energy storage capability (3093.72 F g−1 at 1 A g−1). Furthermore, we fabricated an asymmetric device using Ni/Co-MOF@rGO as a high-rate positive electrode and activated carbon (AC) as a negative electrode (Ni/Co-MOF@rGOǁAC). This hybrid device presents an impressive specific energy of 81.82 W h k g−1, a specific power of 2750 W k g−1, and superior cycling stability (94.7% initial capacity retention after 3700 cycles) at a current density of 1 A g−1. The synergistic effect of metal cores and reduced graphene oxide features in a cold plasma atmosphere produced a hierarchical three-dimensional nanostructure with more electroactive sites, which was advantageous for high-efficiency redox processes. This work clearly states the cold-plasma synthesis of MOF nanocomposite with desired morphological characteristics for energy storage applications.