Graphene Papers with Tailored Pore Structures Fabricated from Crumpled Graphene Spheres

Abstract

Graphene papers have great potential for various applications, such as electrodes in energy storage devices, protective coating, and desalination, because of their free-standing structure, flexibility, and chemical tunability. The inner structures of the graphene papers can affect their physical properties and device performance. Here, we investigated a way to fabricate graphene papers from crumpled reduced graphene oxide (rGO) spheres. We found that ultrasonication was useful for tailoring the morphology of the crumpled graphene spheres, resulting in a successful fabrication of graphene papers with tunable inner pore structures. The fabricated graphene papers showed changes in mechanical and electrical properties depending on their pore structures. In addition, the tailored pore structures had an influence on the electrochemical performance of supercapacitors with the fabricated graphene papers as electrode materials. This work demonstrates a facile method to fabricate graphene papers from crumpled rGO powders, as well as a fundamental understanding of the effect of the inner pore structures in mechanical, electrical, and electrochemical characteristics of graphene papers.

Advances on Emerging Materials for Flexible Supercapacitors: Current Trends and Beyond

“…Along with this, moving forward toward the real‐time application such as wearable energy devices, the flexibility of the graphene is vital and very recently the porosity combined with the flexible graphene papers or otherwise can be called as paper‐like films, produced from the crumbled rGO through vacuum filtration was reported. [ 27 ] The authors here aligned the porous structure as a separator and the as‐prepared graphene papers as the free‐standing binder‐free electrodes. These materials were elaborately studied for EDLC behavior depending on their sonication time, applied during the vacuum filtration method.…”

Synergistic Effect of Graphene/Silver Nanowire Hybrid Fillers on Highly Stretchable Strain Sensors Based on Spandex Composites

“…Therefore, rather than using additional materials, the surface morphology of the graphene powders was modified to improve dispersion. A simple sonication treatment was used as an effective method to transform crumpled shapes into flat surfaces [ 39 ]. The strong shear stresses and cavitation during sonication treatment altered the crumpled morphology of the graphene powders.…”

Electrical Measurements of Thermally Reduced Graphene Oxide Powders under Pressure

“…Previously, we measured the in-plane electrical conductivity of rGO papers directly fabricated from TGF600 rGO powders without any additional reduction [15]. Owing to the spherical morphology of the TGF600 rGO powders, the paper was formed after sonication treatments which rendered the shapes of the powders flatter and unfolded.…”

“…Thus, more sonication treatments enabled the fabrication of rGO papers with more layered stacking and less porosity. In the previous study, an rGO paper fabricated via the sonication of rGO powders for 6 h showed the average electrical conductivity of 152 ± 8 S/m [15]. The density of the rGO paper was estimated to be 0.13 g/cm 3 by using the mass used to fabricate the papers, paper diameter, and paper thickness.…”

“…In contrast, rGO flakes cannot easily form a free-standing paper via vacuum filtration because the crumpled morphology of rGO powders reduces their interfacial contacts, resulting in weak interactions between rGO flakes. Therefore, the morphology of rGO flakes needs to be modified through an additional treatment such as sonication for fabricating a free-standing paper [15]. Compaction of powders in a given space has been an alternative to the electrical measurement of agglomerates of various powders [16].…”