With the rapid expansion of 5G/6G technologies and the growing need for stealth applications, there is an urgent demand for high-performance microwave absorption materials that are thin, lightweight, and effective across a broad frequency range.

A team of scientists has now designed a novel heterostructure composite by integrating nickel-cobalt bimetallic nanoparticles (Ni_0.5Co_0.5 and NiCoO₂) with nitrogen-doped nanoporous carbon. This multi-interface structure creates two types of built-in electric fields semiconductor and Mott-Schottky heterojunctions that work together to promote charge separation and accelerate polarization relaxation.
Experimental results show that the optimized material achieves an exceptional minimum reflection loss of –51.5 dB and an effective absorption bandwidth of 6.4 GHz at a thickness of only 2.8 mm, fully covering the Ku band (11.6–18.0 GHz). This performance exceeds that of most previously reported bimetallic absorbers.

The study demonstrates that engineering dual built-in electric fields is a highly effective strategy for developing advanced microwave absorbing materials with superior bandwidth and minimal thickness, showing great potential for applications in telecommunications and electromagnetic protection.

DOI：10.1016/j.apmate.2025.100344