Combined experiment and simulation on pore structure of graphene aerogel for microwave absorption and thermal insulation

Abstract

The configuration of pore structures is of paramount importance for the microwave absorption and thermal insulation of conductive aerogels. Nevertheless, design methodologies that rely on extensive experimental experience have limited the applicability of conductive aerogels in radar-infrared compatible stealth applications. In this study, finite element simulations of microwave absorption and heat transfer properties are conducted using a simplified two-dimensional model. The wave-absorbing and heat-insulating properties of graphene aerogel as influenced by the pore structure are accurately predicted. The preparation of foamed graphene aerogels with isolated pores was conducted using a surfactant foaming process, with the process guided by simulation predictions. The size, number, and spacing of the bubbles can be flexibly controlled to provide the aerogel with an appropriate density and porosity, which balances the contradiction between the high attenuation capability and the impedance-matching nature. This enables the foamed aerogel to achieve reflection loss of −75.5 dB and ultra-wide effective absorption bandwidth of 9.5 GHz. Furthermore, the low density and isolated pores bestow upon the aerogel material exemplary thermal insulation capabilities, which masked the radiant temperature of a hot object from 135 °C to 50.8 °C. This work offers novel insights and a theoretical foundation for the design of pore structures in radar-infrared compatible stealth aerogels.