Adapting Single-Atom Catalysts to Li-O₂ Batteries: Enhancing Energy Storage

Lithium-oxygen (Li-O₂) batteries (LOBs) are promising candidates for energy storage, primarily due to their remarkable energy density. Yet, the practical implementation of LOBs is hampered by the large overpotentials they require during charging, given the Li₂O₂ they produce is not conductive. This both undermines their energy efficiency and accelerates associated solvent breakdown. Enhancing oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics at cathodes is essential to mitigating these issues, as elevating corresponding activity reduces charge polarization and prolongs battery lifespan, addressing challenges impeding current LOB adaptation. Recently, single-atom catalysts (SACs) garnered interest from LOB researchers for their exceptional catalytic activity, stemming from their maximized surface exposure and related properties. This review first examines SAC structural design and morphological features that contribute to catalytic behavior, then illustrates how theoretical approaches such as density functional theory uncover mechanistic pathways driving SAC performance. This analysis encompasses preferred atomic arrangements, adsorption behaviors, active site charges, and electronic structure modifications relevant to LOBs. Subsequently, this review investigates how SACs influence catalytic efficiency, highlighting their practical value in advancing LOB technology. Last, current obstacles are summarized and prospects of SAC synthesis, analysis, and implementation are discussed, offering insights toward future research directions.