Entropy‐Driven Multi‐Ion Coexistence at Heterogeneous Nanoscale Interfaces of Transition Metal Sulfides with Anomalous Electronic Transport‐Enhancement

Abstract Heterostructures, particularly those with inhomogeneous interfaces, are plagued by interface defects, energy level quantization, and increased electron localization, which result in poor electrical properties and limited applications. The development of interfacial electrical‐enhanced inhomogeneous heterostructures is highly desirable, yet remains a challenge. Herein, a general method is presented for synthesizing bimetallic sulfide inhomogeneous heterostructures through a 3 d metal(M)‐induced entropy‐enhancement approach (M = Ni, Fe, Cu, Mn, and Zn). The entropy‐enhanced heterointerfaces, with dimensions less than 10 nm, promote the coexistence of multiple valence states in a random distribution at the interface, facilitating electron hopping between different metal ions. This phenomenon generates high‐density interface carriers and enables low‐loss electron transport, leading to the anomalous enhancement of interfacial electrical properties. It is demonstrated that the electrically enhanced interfacial behavior of the CoS 2 /NiCo 2 S 4 heterostructure results in a 100–200% improvement in dielectric properties compared to its single‐component counterparts. This enhancement broadens its potential as an effective electromagnetic wave absorber, helping to alleviate electromagnetic pollution. Effective electromagnetic absorption with a bandwidth of 4.64 GHz is achieved at a thickness of 1.5 mm. The work provides new insights into the study of anomalous physical behaviors at high‐entropy interfaces, such as topological states and magnetic properties.