Synergistic Design and Efficient Microwave Absorption Performance of Interface-Engineered Graphene/Graphdiyne Heterostructures

Graphdiyne (GDY) possesses a unique electronic structure; however, its application in microwave absorption is severely restricted by insufficient electrical conductivity and impedance mismatch. Herein, an interfacial engineering strategy is proposed to overcome these limitations. By constructing graphene/graphdiyne (GR/GDY) heterostructures, the interfacial characteristics and charge distribution were effectively modulated, thereby enhancing the electromagnetic wave loss capability of GDY. The intriguing unidirectional growth of GDY on the GR surface is systematically investigated, elucidating the mechanism of liquid–liquid interface-induced lateral epitaxial growth. Through precise optimization of the GR-to-GDY ratio, a 3D sheet-like composite with excellent wave absorption performance was successfully fabricated. The optimized absorber achieved a minimum Reflection Loss (RL_min) of −44.95 dB and a broad effective absorption bandwidth (EAB) of 5.57 GHz at a thin thickness of 2.2 mm. Theoretical calculations and experimental results demonstrate that the superior performance stems from the synergy of interfacial polarization, dipole polarization, and conductive loss, coupled with optimal impedance matching. The construction and structural optimization of the GR/GDY composite absorber provide a strong impetus for expanding the application of GDY in the field of microwave absorption.