Imagine our surprise when reviewing cutting edge research papers to include in our newsletter for February and we find another long time client has published an equally impressive article using our graphene oxide to 3d print graphene aerogel supercapacitors.
Supercapacitors Based on Three-Dimensional Hierarchical Graphene Aerogels with Periodic Macropores
“Graphene is an atomically thin, two-dimensional (2D) carbon material that offers a unique combination of low density, exceptional mechanical properties, thermal stability, large surface area, and excellent electrical conductivity. Recent progress has resulted in macro-assemblies of graphene, such as bulk graphene aerogels for a variety of applications. However, these three-dimensional (3D) graphenes exhibit physicochemical property attenuation compared to their 2D building blocks because of one-fold composition and tortuous, stochastic porous networks. These limitations can be offset by developing a graphene composite material with an engineered porous architecture. Here, we report the fabrication of 3D periodic graphene composite aerogel microlattices for supercapacitor applications, via a 3D printing technique known as direct-ink writing. The key factor in developing these novel aerogels is creating an extrudable graphene oxide-based composite ink and modifying the 3D printing method to accommodate aerogel processing. The 3D-printed graphene composite aerogel (3D-GCA) electrodes are lightweight, highly conductive, and exhibit excellent electrochemical properties. In particular, the supercapacitors using these 3DGCA electrodes with thicknesses on the order of millimeters display exceptional capacitive retention (ca. 90% from 0.5 to 10 A·g−1) and power densities (>4 kW·kg−1) that equal or exceed those of reported devices made with electrodes 10−100 times thinner. This work provides an example of how 3D-printed materials, such as graphene aerogels, can significantly expand the design space for fabricating high-performance and fully integrable energy storage devices optimized for a broad range of applications.
Recently, we utilized an extrusion-based 3D printing technique known as direct-ink writing (DIW), to fabricate highly compressible graphene aerogel microlattices. These 3Dprinted graphene aerogels showed even better mechanical strength than most bulk graphene assemblies while maintaining the large surface area of single graphene sheets. The DIW technique employs a three-axis motion stage to assemble 3D structures by robotically extruding a continuous “ink” filament through a micronozzle at room temperature in a layer-by-layer scheme. The prerequisite for this method is to design gelbased viscoelastic ink materials possessing shear thinning behavior to facilitate extrusion flow under pressure and a rapid pseudoplastic-to-dilatant recovery resulting in shape retention after deposition. Furthermore, the inks’ physical and electrochemical properties can be significantly improved to even realize multifunctionality by the addition of functional fillers, such as conductive nanoparticles, nanotube/wires, as well as nanofibers. Here, we demonstrate a fabrication strategy for 3D-printed graphene composite aerogels (3D-GCAs) with designed architecture for microsupercapacitor applications.”
You can find the full article here http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.5b04965