Multifunctional layered structure graphene aerogel with customizable shape by ion diffusion-directed assembly

Abstract

Aerogels with a layered structure fully leverage the in-plane mechanical, electrical, and thermal properties of two-dimensional building blocks for various engineering applications. However, the layered structure aerogels produced by freeze-casting require bidirectional temperature gradient to direct solid crystal growth, limiting the fabrication of complex macroscopic shapes of aerogels for multifunctional protection in specific situations. Here, we developed an ion diffusion-directed assembly (IDDA) strategy to enable the fabricate layered structure graphene aerogels (LGAs) with customizable macroscopic shapes. Metal ions spontaneously diffuse (concentration difference) into the negatively charged graphene oxide (GO) dispersion from the out-of-plane direction of the substrate and assemble GO to form a layered structure. Preparation of custom-shaped LGAs can be achieved by using IDDA strategy with custom-shaped substrates. Layered structure endows LGAs with super-elasticity (nearly full recovery after 10,000 cycles at 90 % compressive strain) and ultrahigh electromagnetic interference (EMI) shielding performance (an EMI shielding effectiveness of 89.3 dB and a specific shielding effectiveness of 107,850 dB cm²/g). Notably, LGAs can provide efficient electromagnetic protection for customized shapes. Additionally, LGAs exhibit strain-sensitive conductivity, demonstrating excellent compression-induced tunable EMI shielding and sensing performance. This IDDA strategy is extendable to other charged colloidal systems, enabling efficient fabrication of layered aerogels with complex shapes and multicomponent, promising for the practical application of multifunctional aerogels.