A Facile and Scalable Approach in the Fabrication of Tailored 3D Graphene Foam via Freeze Drying

Abstract

One of the challenges in the processing of advanced composite materials with 2D reinforcement is their extensive agglomeration in the matrix. 3D architecture of 2D graphene sheets into a Graphene Foam (GrF) assembly has emerged as an effective way to overcome agglomeration. The highly reticulated network of branches and nodes of GrF offers a seamless pathway for photon and electron conduction in the matrix along with improved mechanical properties. 3D GrF nano-filler is often fabricated by chemical vapor deposition (CVD) technique, which demands high energy, slow deposition rate, and restricting production to small scale. This work highlights freeze-drying (FD) technique to produce 3D graphene nanoplatelets (GNP) foam with a similar hierarchical structure to the CVD GrF. The FD technique using water as the main chemical in 3D GNP foam production is an added advantage. The flexibility of the FD in producing GNP foams of various pore size and morphology is elucidated. The simplicity with which one can engineer thermodynamic conditions to tailor the pore shape and morphology is presented here by altering the GNP solid loading and mold geometry. The FD 3D GNP foam is mechanically superior to CVD GrF as it exhibited 1280 times higher elastic modulus. However, thermal diffusivity of the FD GNP foam is almost 0.5 times the thermal diffusivity of the CVD GrF due to the defects in GNP particles and pore architecture. The versatility in GNP foam scalability and compatibility to form foam of other 1D and 2D material systems (e.g., carbon nanotubes, boron nitride nanotubes, and boron nitride nanoplatelets) brings a unique dimensionality to FD as an advanced engineering foam development process.

Freestanding 3D-interconnected carbon nanofibers as high-performance transducers in miniaturized electrochemical sensors

“…However, the methods suffer from high production cost and inherent complexity, in particular the need for template removal. Template-free based strategies such as hydrothermal technique [2], freeze-drying [3], and electrochemical deposition [4] are much simpler and less expensive, but the integration of the as-fabricated 3D graphene to the miniaturized electrochemical sensor is still an issue, in particular, in terms of mass-production feasibility. Even though 3D-printing of carbon materials promises high throughput manufacturing of electrochemical transducers with convenience, fast and customizable shapes, and designs, the dimensions of electrodes are typically limited to the millimeter range unless sophisticated instrumentation is applied.…”

Porous Flow Field for Next-Generation Proton Exchange Membrane Fuel Cells: Materials, Characterization, Design, and Challenges

“…These methods can be roughly classified into three groups, namely, the self-assembly method, template-directed method, and solvothermal reaction method, with their corresponding schematics given in Figure 5(a)−(c), respectively. In addition, some other novel approaches such as 3D printing methods, 216 supercritical CO 2 fluid techniques, 217 freezing techniques, 218 and electrochemical approaches 219 have also been studied.…”

Graphene-Based Assemblies for Moist-Electric Generation

“…3D printing technology (Wei et al, 2015;Fu et al, 2016;Ponnamma et al, 2021), the sol-gel method (Tang et al, 2014;Xu et al, 2016), direct freeze-drying (Yang et al, 2018b;Thomas and Agarwal, 2021), substrate-assisted reduction and GO assembly (Hu et al, 2013;Zhao et al, 2016a), and laser scribed patterning (El-Kady et al, 2012;Strong et al, 2012), among others (Ervin, 2015), are also effective methods of graphene assembly preparation. Due to their unique advantages, these methods are widely used in graphene assembly research.…”