Liquid metal-encapsulated spherical Al2O3/PVA aerogel composites for high-efficiency electromagnetic interference shielding and enhanced mechanical properties

Liquid metal (LM) is a promising candidate for electromagnetic interference (EMI) shielding due to its exceptional electrical conductivity and ease of processing. However, the high surface tension of LM leads to poor compatibility with polymers, significantly hindering its application in EMI shielding. Here, Al 2 O 3 @LM/borax crosslinked PVA (Al 2 O 3 @LM/BCP) aerogel is prepared using mechanical grinding, melting crosslinking, and directional freeze-drying techniques. The core–shell structure of Al 2 O 3 @LM, prepared by mechanical grinding, effectively reduces the high surface tension of LM, enhancing compatibility with the PVA matrix. Due to its freeze-dried porous structure and superior LM conductivity, the Al 2 O 3 @LM/BCP composite aerogel exhibits outstanding electrical conductivity of 312.5 S/m, efficient electromagnetic interference shielding efficiency (EMI SE) of 80.9 dB, and an excellent SEA/SET ratio of 83.9 %. This work offers a straightforward strategy for developing EMI shielding aerogels with excellent mechanical properties for EMI protection applications.