Preparation Of Dielectric/Magnetic Loss Doped Graphene Aerogel And Its Microwave Absorbing Properties

The development of modern electronic information technology not only brings great progress to our daily life and,but also brings serious electromagnetic pollution problems.Therefore,electromagnetic wave absorbing materials have been paid more and more attention.Traditional absorbing materials have high density and poor stability,which can no longer meet the current needs of absorbing performance.The development of new composite absorbing materials with light weight,broadband and high absorption performance is the key research direction in the field of functional materials.Graphene is widely used in the field of wave absorption,however,the high dielectric constant of single graphene absorbing material is not conducive to impedance matching,resulting in its poor microwave absorbing performance.Combining graphene with magnetic loss material or dielectric materials can effectively improve the electromagnetic matching characteristics and enhance the microwave absorbing performance.Different reduction methods have different effects on the absorbing properties of r GO,and it is found that the r GO aerogel reduced by heat treatment at 300℃has the best electromagnetic wave absorbing properties.The Ni/r GO composite aerogel was obtained by the hydrothermal reduction self-ass embly method and high temperature annealing treatment,and the effect of Ni content on the absorbing performance was analyzed.Ni-10 has a minimum reflection loss of-42.6 d B when the thickness of 2.7 mm and the frequency of 12.22 GHz.Ni chains help not only to enhance the magnetic loss but also to enhance the polarization loss.In addition,the synergistic effect between the loss mechanisms further improves the electromagnetic wave absorption performance of the composites.The Ti O₂/r GO composite aerogel was obtained by one-step hydrothermal reduction and high-temperature annealing.The content of Ti O₂ in the aerogel was controlled by controlling the addition amount of butyl titanate,and the effect of Ti O₂content on the absorbing performance was analyzed.The sample Ti O₂-1 has a minimum reflection loss of-41.9 d B when the thickness of 4.5 mm and the frequency of 12.56 GHz.The introduction of Ti O₂ effectively improves the impedance characteristics of graphene materials and improves the wave absorbing performance.Adding Ti O₂ and Ni at the same time,the obtained sample Ti O₂-2/Ni-10 achieves the minimum reflection loss of-51.9 d B when the thickness of 2.4 mm and the frequency of 15.96 GHz.The wave-absorbing properties of the three-phase composite aerogel Ti O₂/Ni/r GO were further improved,providing a new idea for regulating the wave-absorbing properties.In this paper,the absorbing properties of composites are adjusted by structural design and composition design,and the effects of interface loss,polarization loss,eddy current loss and synergistic effect on the absorbing properties are discussed.It provides a reliable way to achieve the development goal of"thin,light,wide and strong"absorbing materials.