Flexible asymmetric supercapacitor based on Open-Hollow Nickel-MOFs/Reduced graphene oxide aerogel electrodes.

DFT calculation is used to study the electrochemical capacity enhancement mechanism of the fabricated flexible 3D porous rOHNM-AGs electrodes based on open-hollow Ni-MOF microspheres with high mechanical strength and superior electrochemical properties. [Display omitted] • 3D rOHNM-AGs are achieved by embedding open-hollow Ni-MOF microspheres into graphene nanosheets. • DFT calculation reveals charge-transfer interaction between the rOHNM-AGs and OH– ions. • The rOHNM-AGs/KOH/PVA film can be twisted with different angles, which can lift 500 g plastic bottle. • The fabricated rOHNM-AGs electrode exhibit superb specific capacitance of 1644F·g−1 at 1 A·g−1. • A portable multifunctional instrument can be powered by all-solid-state supercapacitor device for 15 mins. Metal-organic frameworks (MOFs) are extensively used for electrode materials of supercapacitors under their unique characteristics like customizable pore size, plentiful active sites and tunable structure. However, the MOFs lack adequate electrical conductivity and satisfactory stability, when directly applied to supercapacitor electrode materials, limiting the further improvement of their electrochemical properties. Accordingly, three-dimensional porous aerogels (rOHNM-AGs) have been achieved by embedding open-hollow nickel-based metal–organic framework microspheres between graphene layers. Under the controllable and highly ordered metal nodes as well as organic linkers, the prepared rOHNM-AGs still reserve the preponderance of MOF materials with multifarious exceptional constituent and configurational benefits. Furthermore, the remarkable electrical conductivity from graphene leads to a significant increase in electron/ion transport rate. In addition, charge-transfer interaction between the acceptor of OH– ions and the donor of rOHNM-AGs has been exposed by the density functional theory calculations. Moreover, a pliable and high tensile rOHNM-AGs/PVA/KOH film electrode has been fabricated by the PVA/KOH gel-electrolyte, which is capable of curving at multifarious angles. For actual utilizations, the manufactured supercapacitor apparatus can run a multi-purpose display for over 15 mins. Therefore, this groundbreaking research furnishes a new inspiration for preparing composite electrodes based on MOFs and graphene for flexible asymmetric supercapacitors. [ABSTRACT FROM AUTHOR]