Achieving super-broad effective absorption bandwidth with low filler loading for graphene aerogels/raspberry-like CoFe2O4 clusters by N doping

• Published in: Journal of colloid and interface science Vol. 590; pp. 186 - 198
• Main Authors: Wang, Xiangyu, Liao, Jun, Du, Rongxiao, Wang, Guohui, Tsidaeva, Natalia, Wang, Wei
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.05.2021
• Subjects: A. Multifunctional composites; absorption; aerogels; B. Physical properties; D. Surface analysis; E. Performing; graphene; graphene oxide; magnetism; D. Surface analysis; B. Physical properties; E. Performing; A. Multifunctional composites
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2021.01.069

[Display omitted] •N-rGA decorated with pomegranate-like CFO clusters forms 3D porous networks.•RLmin reaches up to −55.43 dB at 15.36 GHz and 2.3 mm with a filler loading of 10 wt%.•A super-wide effective absorption bandwidth of 7.28 GHz is obtained at 2.53 mm.•At 3.3 mm, the effective absorption bandwidth completely covers X-band. A unique three-dimension (3D) porous network structure where N-doped reduced graphene oxide aerogels (N-rGA) are decorated by raspberry-like CoFe2O4 (CFO) clusters. Super-broad effective microwave absorption bandwidth (7.28 GHz) of the CFO/N-rGA composite is obtained at 2.53 mm by changing N contents. Here, the dipolar relaxation loss and conduction loss are highly sensitive to the presence of pyridinic, pyrrolic and graphitic N in the CFO/N-rGA composites. A minimum reflection loss of the CFO/N-rGA composites reaches up to −55.43 dB at 15.36 GHz with a matching thickness (2.3 mm) and low filler loading (10 wt%). Its effective absorption bandwidth completely covers X-band from 7.76 to 12.72 GHz at 3.3 mm. The high-efficiency microwave absorption of the composites mainly results from the enhanced polarization relaxation, the specific design of conductive network and the superior impedance matching. This study offers a promising technical route to explore new N-doped magnetic/dielectric composites as ideal microwave absorbers.