Researchers from the Lawrence Livermore National Laboratory were able to produce microlattices with graphene aerogel using engineered architecture through a 3D-printing technique called direct ink writing. According to them, this new graphene aerogel type will improve energy storage, nanoelectronics, sensors, separations and catalysis, among others.
Also known as "liquid smoke," aerogel is a synthetic, ultralight porous material made from a gel, where the liquid component has been replaced with gas. The 3D-printed graphene aerogels feature high surface areas and mechanical stiffness despite being lightweight, conduct electricity and exhibit compressibility up 90 percent of compressive strain. Additionally, the microlattices showcase dramatic improvement over bulk graphene materials and facilitate mass transport.
Random pore structures were produced in previous attempts at manufacturing bulk graphene aerogels, excluding the material's ability to customize transport and various other mechanical properties specific to certain applications, such as pressure sensors, flow batteries and separations.
"Making graphene aerogels with tailored macro-architecture for specific applications with a controllable and scalable assembly method remains a significant challenge that we were able to tackle," said Marcus Worsley, co-author of a paper published in the journal Nature Communications.
He explained that 3D printing has the ability to offer intelligently designed aerogel pore structure, allowing control over mass transport and optimizing physical properties like stiffness. Worsley and colleagues are also confident that the creation of the graphene aerogel will open up the design space for aerogel as a medium for creative and novel applications.
Cheng Zhu, also a co-author of the paper, added that adapting 3D printing technology to aerogels made it possible to create numerous architectures for applications that have not been achieved before.
To create the microlattices, graphene oxide inks were made by combining an aqueous suspension with silica filler, forming a highly viscous, homogenous ink. The resulting ink was then loaded into a syringe barrel before being extruded through a micronozzle to produce 3D structures.
"To demonstrate 3D printing of graphene aerogels, we first printed woodpile, ‘simple cubic'-like lattices consisting of multiple orthogonal layers of parallel cylindrical filaments successively printed in a layer-by-layer fashion," wrote the researchers.
Other co-authors of the paper include: Christopher Spadaccini, Joshua Kuntz, Alexandra Golobic, Eric Duoss and Yong-Jin Han. The Laboratory Directed Research and Development Program provided funding support for the study.
