Nanoporous Liquid Metal Silica Aerogels for Solar Energy Capture and Heat Transfer

Light-responsive and thermally conductive materials with high efficiency for energy absorption from sunlight can greatly address challenges in solar energy harvesting and heat transfer. Here, a liquid metal (LM) silica aerogel composite with a high photothermal conversion ability and thermal conductivity is introduced. In this composite, EGaIn (eutectic alloy of gallium (Ga) and indium (In)) LM nanoparticles act as light-absorptive components, while the porous aerogel enhances light penetration with minimal use of LM. The interconnected LM nanoparticles create a network enabling thermal conductance and heat transfer throughout the composite. With the overall absorbance of approximately 85%, the LM aerogel at 9.5% LM of the aerogel volume exhibits a high photothermal conversion ability by quickly increasing the temperature to ∼50 °C under standard 1 sun in ambient air. Additionally, the LM silica aerogel composite is assessed to have a high stability when used for water heating. The work presents the potential of the LM silica aerogel in solar energy harvesting and thermal management systems while also showing the advantages of this lightweight, porous aerogel architecture.