Synthesis of graphene nanocomposites integrated with 3D bimetallic magnesium/cobalt metal-organic framework as anodic material for solid-state asymmetric supercapacitors

Abstract

In this study, we have grown 3D porous bimetallic Mg/Co MOF in the presence of exfoliated graphene nanoplates (EGNPs) via a one-step in-situ hydrothermal process, where 1,3,5-benzenetricarboxylic acid (BTC) was used as an effective organic linker since it is cost-effective and EGNPs served as a conductive component. Morphological characterization of Mg/Co-BTC MOF@EGNP nanohybrid confirmed the homogeneous growth of ball-shaped Mg/Co-BTC MOF around the graphene nanoplates, while nitrogen adsorption-desorption analysis revealed large surface area with a high volume fraction of mesopores. This surface features is highly favorable for rapid ion/electron transportation that ensures high specific gravimetric capacitance (838 F/g) and noticeable rate capability (81 % capacitance retention). As-synthesized nanohybrid was used as anode material to construct a prototype all-solid-state asymmetric supercapacitors (ASC) device with a significantly high energy density of 73.82 Wh kg−1, a wide potential window of 0–1.7 V, admirable capacitance retention of 95.1 % after 8000 cycles, and long self-discharge time. Moreover, these capacitance performances also demonstrates the reliability of the as-synthesized poly vinyl alcohol (PVA)-Li2SO4 membrane as a separator-cum-electrolyte for fabrication of future leakage-proof ASCs for wearable electronics. This work can lead to manufacting innovation in the future.