Nanoarchitectonics of MnO2 nanotubes as sea urchin-like aggregates for dielectric response and microwave absorption with a wide concentration domain

Designing highly reliable and practical microwave absorbers is one of the most important research directions in the microwave absorbing field. Many absorbents suffer from concentration-sensitivity and environmental-sensitivity dilemmas in practical applications. Here, sea urchin-like aggregates of MnO2 nanotubes were synthesized by a simple hydrothermal method, which exhibit an outstanding impedance matching characteristic. The composites based on sea urchin-like aggregates of MnO2 nanotubes show excellent microwave absorption performance in a wide concentration domain from 20 wt.% to 70 wt.%, corresponding to electrical conductivities from 1.86 x 10(-7) to 1.85 x 10(-5) S/m. Such a wide concentration range of absorbent for excellent microwave absorption is mainly attributed to the beneficial impedance matching properties of sea urchin-like aggregates of hollow nanotubes. A competitive absorption bandwidth of 3.36 GHz is achieved at 1 mm thickness, which can be broadened to 13.4 GHz by structural design. This work shows a new scheme for designing reliable and practical microwave absorbers benefit from the wide absorbent concentration domain.

Automated summary

Designing highly reliable and practical microwave absorbers is crucial in the field of microwave absorbing research. This study presents a novel approach by synthesizing sea urchin-like aggregates of MnO2 nanotubes, which exhibit outstanding microwave absorption performance over a wide concentration range. The designed absorbers show a competitive absorption bandwidth and provide a new scheme for reliable and practical microwave absorber design.