The compression mechanical properties of graphene aerogel

Lulu Niu,Guangyong Li,Pengwan Chen,Jing Xie,Xuetong Zhang,F Gálvez Díaz-Rubio,D.A Cendón Franco

doi:10.1051/epjconf/202125006010

Abstract

Graphene aerogel (GA) samples, prepared by the Sol-Gel method, were tested under quasi-static and dynamical compression, and characterized via surface area analyzer and scanning electron microscopy. The results show that the drying method has a significant influence on the sample’s microstructure as well as its mechanical compression properties. The supercritical CO2 dried sample has a notable higher specific surface area, and higher compression strength; although the freeze dried sample is much lighter than the supercritical CO2 dried sample, it exhibits a nonlinear superelastic behavior and large compressibility with a reversible strain up to 94%; under the dynamic compression test, the supercritical CO2 dried sample presents a negative Poisson’s ratio behavior whereas the flower-like failure pattern was observed for the freeze dried sample. GA, therefore, is a promising candidate for energy absorption purposes because of its very low density, high specific surface area and porous microstructure.

Highlights

Graphene is a one-atom-thick layer of carbon atoms arranged in a hexagonal lattice (1)
The specific surface area of graphene aerogel (GA) prepared by supercritical CO2 drying is 530.87 m2∙g-1, which is higher than the MoS2 aerogel (18 m2∙g-1) (12), graphene-CNT aerogels (315 m2∙g-1) (13), silica aerogels (450 m2∙g-1) (14) and the 3D polypyrrole-graphene foam (463 m2∙g-1) (15)
Compared with the freeze drying, the GA samples prepared by the supercritical CO2 drying have a higher compression strength

Summary

Introduction

Graphene is a one-atom-thick layer of carbon atoms (approximately 0.4 nm) arranged in a hexagonal lattice (1). Certain methodologies have been devised to prepare three-dimensional (3D) structure graphenes such as aerogels (4), hydrogels (5) and cellular monoliths (6). Among these structures, the aerogel shows a great promise because it can be lighter than air and has attracted much attention in recent years (7). The aerogels are prepared from molecular precursors (generally graphene oxides) by sol-gel methods and followed by either freeze or supercritical drying to replace the solvents with air (9). Laboratory hypervelocity impact experiments conducted by Japanese scientists have verified that at impact velocities below 6 km/s the projectiles of aluminum oxide, olivine, or soda lime glass with diameters ranging from 10 to 400 μm were captured without fragmentation by the silica aerogel collector of 0.03 g∙cm-3 (11). The graphene aerogel (GA) was test mechanically (quasi-static and dynamical) for exploring its potential application in the field of energy absorption as a lightweight material

Methods

Results

Conclusion