Enhanced electromagnetic wave absorption properties of Ni–SnO2 core–shell composites synthesized by a simple hydrothermal method

•The core–shell Ni/SnO2 composites were synthesized by a facile hydrothermal method.•The microwave absorption properties of Ni/SnO2 were improved compared with raw Ni.•The minimum reflection loss of Ni/SnO2 was −18.6 dB at 14.7 GHz.•The good properties were attributed to core–shell structure and impedance matching.

The core–shell Ni/SnO2 composites were synthesized through a facile hydrothermal method using Ni microspheres as cores, SnCl2 as stannum source, and H2O2 as the oxidizing agent. The microwave absorption properties of Ni microspheres and Ni/SnO2 composites were investigated at 1.018.0 GHz. It was shown that the reflection loss (RL) of Ni/SnO2 paraffin-composite can be evidently enhanced compared with Ni microspheres paraffin-composite, and the minimum value is −18.6 dB at 14.7 GHz. The enhancement mechanism was discussed based on complex relative permittivity (εr=ε'−jε″) and relative permeability (µr=µ'−jµ″).