Lightweight,Low-Cost Co2SiO4@diatomite Core-Shell Composite Material for High-Efficiency Microwave Absorption

The porous and biomimetic cobalt silicate@diatomite (Co₂SiO₄@diatomite) was successfully synthesized by a two-step method, including the hydrothermal method and calcination to improve the electromagnetic wave absorption property. Different hydrothermal times were well-tuned for Co₂SiO₄@diatomite composites with different loadings of Co₂SiO₄. Interestingly, the Co₂SiO₄@diatomite composites (6 h, 25 wt%) had a smaller minimum reflection loss. Moreover, the minimum reflection loss (RL_min) could reach −12.03 dB at 16.64 GHz and the matched absorber thickness was 10 mm, while the effective absorption bandwidth (EAB, RL ≤ −10 dB) could be 1.92 GHz. In principle, such findings indicate that Co₂SiO₄@diatomite nanocomposites could be a promising candidate for high-efficiency microwave absorption capability.