Transition Metal and Derivative-Based Aerogels for Microwave Absorption

Transition metals and their derivatives have demonstrated considerable potential in the field of electromagnetic wave absorption owing to their complementary dielectric and magnetic loss capabilities. However, achieving satisfactory impedance matching with pure transition metal-based materials remains challenging, which restricts the operational frequency bandwidth and limits the minimal thickness. Aerogels, with their unique 3D porous networks, high porosity, large surface area, and ultra-low density, offer an ideal supporting matrix for hosting transition metals and their derivatives. Such composite structures not only improve impedance matching but also introduce diverse attenuation mechanisms, thereby enabling superior electromagnetic wave absorption performance. This review begins with a systematic introduction to the fundamental mechanisms of electromagnetic wave absorption. It subsequently summarizes the design strategies for aerogel architectures from the perspective of gelation principles, categorizes various types of aerogel-based composites incorporated with transition metals and their derivatives, and highlights recent research advances in this emerging field. Finally, the current challenges and future prospects for the development of transition metal-based aerogel absorbers are outlined. This comprehensive overview is intended to illuminate the path for the rational design of next-generation, high-performance microwave absorbers with integrated multifunctionality.