Multi-scale doping-Induced impedance matching of graphene aerogel enables ultra-broadband microwave absorption

Microwave Absorbing Materials (MAMs) are emerging as a potent solution for addressing electromagnetic waves (EMW) pollution. However, MAMs often exhibit narrowband absorption due to difficulties in achieving optimal impedance matching and sufficient internal loss across an extensive frequency spectrum. Herein, a multi-scale doping strategy is proposed for producing graphene-based aerogel absorbers (FG-Pc@Mn3O4) with ultra- broadband absorption performance. At the microscopic scale, the extremely high electronegativity of C-F bonds creates a strong electron attraction effect and promotes the transformation of carbon atoms from sp2 to sp3, thus disrupting the original conjugated system of reduced graphene oxide (rGO). This effectively reduces the number of free electrons available for conducting electricity and limits the electron migration rate, resulting in the low conductivity of FG-Pc@Mn3O4. At the macroscopic scale, by integrating phthalocyanine (Tph) pulled Mn3O4 particles onto the fluorinated graphene (FG) nanosheets to confer weak magnetic properties on FGPc@Mn3O4, thus allowing FG-Pc@Mn3O4 to exhibit good electromagnetic wave loss ability. Consequently, the synergistic interplay between low conductivity and weak magnetism endows FG-Pc@Mn3O4 with the capacity to absorb 99 % of EMW across the 8.77 to 18 GHz frequency range. This innovative aerogel design provides a feasible and effective idea for advanced level broadband absorbent material technology.