3D Printable concentrated liquid metal composite with high thermal conductivity

Heat dissipation materials in which fillers are dispersed in a polymer matrix typically do not exhibit both high thermal conductivity (k) and processability due to a trade-off. In this paper, we fabricate heat dissipation composites which overcome the trade-off using liquid metal (LM). By exceeding the conventional filler limit, ten times higher k is achieved for a 90 vol% LM composite compared with k of 50 vol% LM composite. Further, an even higher k is achieved by introducing h-BN between the LM droplets, and the highest k in this study was 17.1 W m^-1 K^-1. The LM composite is processable at room temperature and used as inks for 3D printing. This combination of high k and processability not only allows heat dissipation materials to be processed on demand under ambient conditions but it also increases the surface area of the LM composite, which enables rapid heat dissipation.