Enhanced Structure Ductility and Sodium Storage Kinetics of High‐Capacity Sulfide Anodes via Medium‐Entropy Engineering

(7 C) with robust long-term stability. By quantitatively linking elastic constants to ion-transport barriers and failure tolerance, this work elevates ductility as a primary design handle for high-capacity, large volume change anodes. Medium-entropy engineering thus offers a general and scalable route to entropy-stabilized sulfides and other conversion/alloying anodes, enabling mechanically resilient and kinetically fast sodium storage.