Graphene-based supercapacitors as flexible wearable sensor for monitoring pulse-beat

Abstract

Low-dimensional graphene-based nanomaterials have received great attentions in the recent years, but efforts based on using the two dimensional (2D) graphene-based nanomaterials are still rarely made over the past years for fabricating the flexible wearable electronics sensor. In this work, we report on employing the highly conductive polyoxometalate (POM) and 2D graphene nanosheets (2D GNs) to fabricate a type of graphene-based supercapacitors that can detect the pulse beat rate. On the basis of structural information characterized by the X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDs), we find the POM can disperse into the surface of the 2D GNs, thereby forming the POM/2D GNs nanocomposites. With galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) result, we reveal that when compared to the 2D GNs, dispersing the POM into the 2D GNs can improve significantly the cycling stability of POM/2D GNs. Through repeatedly depositing and removing the water droplet that use for modeling the external pressure, we find the as-designed flexible wearable electronics sensor fabricated by depositing the POM/2D GNs on a flexible conductive adhesive substrate is sensitive to the external beat, which, together with the advantages of thin, extremely sensitive, and highly flexible, therefore can be suggested for the human health that is reflected by the pulse-beat.