Mitigating supercooling in liquid metal phase change materials

Abstract

Gallium possesses high thermal conductivity and a rapid heat response rate, making it a promising material for thermal storage in electronic devices. It absorbs a significant amount of heat in the form of latent heat during the melting process, enabling the storage of large amounts of heat in a small volume. However, there is a need to address the challenge of supercooling, particularly at lower temperatures, where the liquid-to-solid phase transition does not occur. In this study, we charged liquid gallium into a porous copper foam with the surface oxide removed, creating a porous Ga/Cu sample. By increasing the heterogeneous surface area of gallium and forming CuGa2 at the gallium-copper interface, we reduced the activation energy required for the liquid-to-solid phase transition. Through repeated heating and cooling cycles, the porous Ga/Cu sample consistently alleviated supercooling, recovering to a solid state and undergoing phase transition from solid to liquid in all heating phases, absorbing heat in the form of latent heat. These findings suggest the potential of utilizing gallium as an excellent heat storage element for downsizing thermal management and cooling systems in electronic devices.