Atomic solvent for tailorable high-entropy ceramics synthesis

High-entropy ceramics (HECs) exhibit important potential as functional materials due to their tunable compositional variations and unique lattice distortions. However, conventional HECs synthesis requires extreme temperatures, often leading to volatilization of low-melting-point elements and imprecise composition control. Herein, we propose a Galinstan atomic solvent strategy for the synthesis of HECs by rapidly altering the ceramics composition through the liquid metals (LMs) interface and the metal salt solution interface reactions at low temperatures (60℃). LMs is used as a dynamic solvent to increase configurational entropy and produce strong negative configurational entropy, providing a strong thermodynamic driving force for uniformity and phase stability. In-situ liquid-cell transmission electron microscopy observation directly captures the dynamic formation process, showing the elements' absorption and mixed crystal coprecipitation. Thermodynamic theory and density functional theory computations confirm that systems incorporating Galinstan exhibit a 1.61-fold enhancement in the reduction of the Gibbs free energy of mixing. Notably, perovskite, rock-salt, and pyrite crystal structures can be tuned through ion substitution, enabling tailored applications in electrocatalysis, ultra-high temperature insulation, and thermoelectric sensors. Hence, the atomic solvent strategy provides a generalizable platform for designing HECs, enabling the realization of tailored phases optimized for specific applications.