Intrinsically microstructured graphene aerogel exhibiting excellent mechanical performance and super-high adsorption capacity

Abstract

Highly porous graphene aerogels (GAs) demonstrate extensive applications in damping blocks, thermal insulation, sensors, catalyst carriers and energy storage because of their ultralow density, superelasticity and functional versatility. These properties have been regulated by topological structural design and composite of materials, but the effect of the structural unit on the properties of GA has not been reported. Herein, highly porous GAs with excellent mechanical performances and improved adsorption capacities have been prepared by a freezing-drying process. Ultra-flyweight (ρ < 1 mg cm−3), superelastic (low energy loss factor) and high-strength (i.e., high Young’ modulus) aerogels can be obtained by integrating different wall thicknesses and pore sizes. And it has been found that the grain refinement of ice crystals has a positive impact on the strength and modulus of as-prepared GAs during freezing-drying, which is similar to typical Hall-Petch strengthening in fine crystal metal materials. The as-prepared GA with the thinnest wall thickness exhibits the highest adsorption properties with respect to the oil solvents, and the adsorption capacity is 1272 times of its own weight. This study enriches our understanding of the structure and performance of GAs and indicates a practical methodology to ensure precise structural control of high-performance GAs for various applications.