Cost-effective preparation and high performance of high-temperature electromagnetic wave absorbing materials based on graphene nanosheets

Abstract

High cost and resistance to harsh working conditions are challenges faced by most microwave absorbers for wide applications. Here, a low-cost graphene-based high-temperature microwave absorbing material is prepared. When the ratio is adjusted appropriately, excellent absorbing performance can be achieved at room temperature: C-2 is the most efficient material with respect to microwave absorption: it has an effective absorption bandwidth as wide as 4.6 GHz, and the minimum reflection is −39.2 dB with a thickness of 1.5 mm. Using the permittivity and TG data of the composites at 800 °C attained, it is demonstrated that the decomposition temperature of composites can be increased from 450° to 820°. When the mass ratio of graphene nanosheets and water glass is 1:2, the composites have the best high-temperature microwave absorption performance: C-2 exhibited the microwave absorption ability with a minimum reflection loss value of approximately −29.6 dB at 16.4 GHz, a thickness of 1.5 mm even at 800 °C.