Controllable design of multi-shell hollow Co3O4/graphite nanosheets composite with broadband microwave absorption performance

In the pursuit of high-performance electromagnetic wave (EMW) absorbing materials, achieving both strong absorption and broad bandwidth remains a significant challenge. The reasonable and effective design of special microstructures is a crucial aspect for achieving efficient microwave absorption performance in electromagnetic wave absorbing materials. This study presents a breakthrough by designing a novel multi-shell hollow Co₃O₄/graphite nanosheets (ms-Co₃O₄/GNs) composite integrated with dielectric MoS₂ layers via a precise-regulated solvent thermal bonding annealing method, which demonstrates exceptional microwave absorption properties. The optimized MoS₂/Co₃O₄/GNs composites exhibit superior electromagnetic wave absorption properties with a remarkable minimum reflection loss of −49.3 dB at an ultrathin thickness of 1.5 mm. Furthermore, the composite achieves an ultra-wide effective absorption bandwidth (EAB, RL ≤ −10 dB) of 4.96 GHz at just 1.8 mm, covering critical frequency ranges for 5G and radar applications. The superior wave-absorbing properties primarily stems from its unique multi-shell hollow structure, abundant heterogeneous interfaces, and the optimized, nearly perfect impedance matching characteristics. This work not only advances the development of Co₃O₄-based absorbers but also provides a generalizable strategy for designing lightweight, broadband, and high-strength EMW absorption materials through intelligent microstructure engineering.