Local Structure Strategies Promoting Lead-Free Dielectric Energy-Storage Applications

Dielectric capacitors are essential for high-power, fast-response electronics, but their performance is limited by trade-offs between high polarization, low hysteresis loss, and high breakdown strength. The urgent need for eco-friendly materials has spurred intense interest in lead-free oxide dielectrics. Recent advances in synthesis and advanced characterization have revealed that atomic- and nanoscale local structures exert a profound influence on energy-storage performance. Specifically, local polar nanoregions, chemical inhomogeneities, lattice distortions, and interfacial architectures play a pivotal role in regulating polarization configuration, leakage behavior, and breakdown pathways. This review systematically summarizes recent progress in lead-free dielectric oxides through local structural design. After a concise overview of dielectric energy-storage principles and classification, representative systems are discussed, with a focus on how specific local structural motifs correlate with macroscopic performance. The emerging strategies, such as local chemical framework design, high-entropy approaches, polar nanodomain engineering, local microstructure architectures, multiphase/heterogeneous interfaces, and local amorphous design, are summarized. By integrating key advances in this field, the review clarifies intrinsic structure-property relationships, identifies current challenges, and outlines opportunities for future breakthroughs, which could deliver timely guidance for designing high-performance and environmentally benign dielectric capacitors.