A general finite-gel strategy for highly concentrated liquid metal inks

Producing high-concentration liquid metal (LM) inks is highly desirable for next-generation flexible electronics, and yet remains a dulling challenging due to the large surface tension and high density of LM droplets. Herein, a general finite-gel strategy is proposed to enable the fabrication of high-concentration liquid metal (LM) inks. In the LM-based inks, the LM droplets are confined in the relaxed finite-gel networks, which provide strong repulsive effects to avoid the reunition of the adjacent LM droplets. The unique structure imparts the LM-based inks with a good colloidal stability even at a very high LM concentration of 30,000.0 g/L. The LM-based inks also present tunable rheological behavior and are suitable for various processing technologies. Moreover, the proposed finite-gel strategy is scalable, and could be expanded to various cryogel systems (e.g., curdlan, gelatin, and gellan gum). This work takes a crucial step forward to producing highly concentrated LM-based inks for flexible electronics. Liquid metal inks are promising for flexible electronics, but it is challenging to produce liquid metal inks due to surface tension and density. Here, the authors design a liquid metal-cryogel system to increase liquid metal concentration.