Diffusion-Mediated Synthesis of Durable High-Entropy Sulfide Nanocrystals: Le Chatelier-Driven and Electron...

Precise control over the microstructures of high-entropy ceramic nanocrystals (HEC NCs) has expanded their emerging applications. The immiscibility challenges arising from elemental differences necessitate extreme reaction conditions, albeit at the expense of controllability. Here, we demonstrate that diffusion-mediated gas-phase cation exchange (DGCE) within ZnS NCs achieves precise structural regulation in high-entropy sulfide nanocrystals (HES NCs) under mild conditions. This process is driven by the removal of ZnCl₂, which shifts the equilibrium according to Le Chatelier's principle to facilitate cation diffusion. Critically, the diffusion kinetics are governed by magnetic and electronic reorganization, whereby cations undergoing spin reorientation or electron transfer (e.g., Fe²⁺, Co²⁺, Ni²⁺) encounter higher activation energies, while those devoid of such coupling (e.g., Cu⁺, Cd²⁺) diffuse more readily. Harnessing this mechanism enables the deliberate engineering of HES NCs with tailored dimensions, compositions, phases, and local structures. The resulting HES NCs exhibit superior thermal, electrochemical, and device stability. An anion-exchange membrane water electrolyzer incorporating Fe_0.21Co_0.19Ni_0.17Cu_0.38Zn_0.24S nanoparticles (NPs) achieves 1 A cm^-2 at 1.74 V and stable operation for over 1500 h. This work provides fundamental insights into the controlled synthesis of HEC NCs with implications for diverse fields.