Reduced graphene oxide/NiO composite (RGO/NiO) was synthesized by a facile pyrolyzation process. The NiO nanoparticles with a small size of about 10-50 nm are uniformly dispersed onto the thin graphene nanosheets. The as-prepared RGO/NiO composite shows excellent microwave absorbability. The obtained composite with a coating layer thickness of 3.5 mm exhibits a maximum absorption of -55.5 dB at 10.6 GHz. And in particular, the product with a coating layer thickness of only 3.0 mm possesses a bandwidth of 6.7 GHz (from frequency of 10.2 to 16.9 GHz) corresponding to reflection loss at -10 dB (90% absorption). Thus, the as-prepared RGO/NiO composite is a very promising EM wave absorbing material as lightweight and high-performance. (C) 2014 Elsevier B.V. All rights reserved.