Ultralight graphene aerogel enhanced with transformed micro-structure led by polypyrrole nano-rods and its improved microwave absorption properties

By a simple one-step reduction self-assembly process, a three-dimensional composite material graphene/polypyrrole aerogel (GPA) has been fabricated. The polypyrrole nanorods (PNRs) not only act as a spacer to avoid the graphene sheets aggregation and enhance mechanical strength but also effectively adjust the permittivity of GPAs to gain expected microwave absorption (MA) performance. Compared with pure graphene aerogel (GA), these aerogels with the ultralow density of around 0.020   g/cm 3 show improved MA performance that the maximum reflection loss (RL) can reach −51.12   dB at the frequency of 6.4   GHz, and the effective absorption bandwidth (RL   <   −10   dB) was 5.88   GHz (10.48–16.36   GHz) corresponding to an absorber thickness of 3.0   mm. Such outstanding MA performances are attributed to the polarization and relaxation process that is correlated with the transformed microstructure of GPAs.