Sustainable Thermal Regulation of Electronics via Mitigated Supercooling of Porous Gallium-Based Phase Change Materials

Gallium liquid metal is one of the promising phase change materials for passive thermal management of electronics due to their high thermal conductivity and latent heat per volume. However, it suffers from severe supercooling, in which molten gallium does not return to solid due to the lack of nucleation. It may require 28.2 degrees C lower temperature than the original freezing point to address supercooling, leading to unstable thermal regulation performance along fluctuations of cooling condition. Here, gallium is infused into porous copper in an oxide-free environment, forming intermetallic compound impurities at the interfaces to reduce the activation energy for heterogeneous nucleation. The porous-shaped gallium provides approximate to 63% smaller supercooling than that of the bulk type due to large specific surface area (approximate to 9,070 cm2 per cm3) and high wetting characteristics (approximate to 16 degrees of contact angle) on CuGa2 intermetallic layer. During repetitive heating-cooling cycles, porous-shaped gallium consistently shows propagation of crystallization at even near room temperature (approximate to 25 degrees C) while maintaining stable performance as thermal buffer, whereas droplet-shaped gallium is gradually degraded due to partial-supercooled state. The findings will improve the responsive thermal regulation performance to relieve a rapid increase in temperature of semiconductors/batteries, and also have a potential for energy storage applications. Gallium liquid metal is a fascinating phase change material (PCM) due to its high thermal properties. However, supercooling restricts its suitability for thermal applications. Here, sustainable thermal regulation performance of gallium-based PCM is demonstrated by increasing possibility of heterogeneous nucleation at the interface between a porous Cu structure and the infused gallium liquid metal. image