Atomic-Level Defect Engineering: From Fundamental Mechanisms to Applications in Energy Materials

Next-generation energy materials require atomic-scale control to overcome persistent limitations in catalytic activity, ion transport, interfacial stability, and durability. Atomic-level defect engineering offers a practical framework by treating defects as designable functional units rather than passive imperfections. This review summarizes how point defects and extended defects regulate electronic structure, ion/mass transport, chemical activity, and structural stability through descriptors such as formation energy, charge state, local coordination, migration barrier, strain field, and interfacial energy. It also highlights characterization-guided defect engineering, in which advanced imaging, spectroscopy, operando measurements, and theoretical modeling enable defect identification, quantification, dynamic tracking, and feedback optimization. Building on these principles, representative applications are discussed across single-atom catalysts, lithium-based batteries, and perovskite solar cells. In single-atom catalysts, vacancy and coordination defects stabilize isolated metal atoms, tune adsorption energetics, and regulate active-site evolution. In lithium-based batteries, defect chemistry, disorder engineering, functional interfaces, and grain-boundary design improve cathode stability, anode kinetics, solid-electrolyte safety, and Li-metal interphase durability. In perovskite solar cells, passivation, interface modification, dimensionality engineering, and defect-source control suppress recombination, ion migration, and degradation. Finally, key challenges in predictive modeling, operando characterization, scalable synthesis, and coupled defect systems are discussed.