▎ 摘　　要

Ferromagnetic metal nanoparticle/graphene nanocomposites are promising as excellent electromagnetic (EM) wave absorption materials. In this work, we used a facile method to synthesize a cobalt nanoparticle-graphene (CoNP-G) nanocomposite. The obtained CoNPs-G exhibited a saturation magnetization (M-s) of 31.3 emu g(-1) and a coercivity (H-C) of 408.9 Oe at 298.15 K. In particular, the CoNPs-G nanocomposite provided high-performance EM wave absorption with multiband, wide effective absorption bandwidth, which was mainly attributed to the synergy effects generated by the magnetic loss of cobalt and the dielectric loss of graphene. In the range of 2-18 GHz, the sample (55 wt% CoNPs-G) held three effective reflection loss (RL) peaks (frequency ranges of 2.4-3.84, 7.84-11.87 and 13.25-18 GHz, respectively, RL