As an emerging functional material, the liquid metal has demonstrated its encouraging potential in several areas with practical trials, while its global uniformity including high density and limited macroscopic interface might become a barrier for some tough application scenarios. Here, we proposed the concept of liquid metal foaming via decomposition agents, aiming to develop a generalized way to make porous foam metallic fluid, which would pave the way in achieving more structured features and adaptability of liquid metals. By introducing a greenness strategy with the help of an ecofriendly foaming agent, we realized a series of designed targeted liquid metal foams (LMFs). Compared with common liquid metals, LMFs possess many excellent properties, such as abundant interfaces, tunable conductivity, and adjustable stiffness, due to the controllable regulation of their porous structure. According to these unique characteristics, diversified values of LMFs were obtained. Benefiting from the naturally enriched interface in LMFs, the hydrogen evolution of LMFs in neutral deionized water was more efficient and more productive. Additionally, the compact LMF-air battery with high performance was originally manufactured. Moreover, the tunable LMF-enabled four-dimensional (4D) electromagnetic shielding materials possess excellent shielding performance. This material could open up broad vistas for the application of LMs.
Keywords: electromagnetic shielding; foam; hydrogen generation; liquid metal foam-air batteries; liquid metals.