Can single-atom precision rewire the electrochemical logic of Li-S chemistry? A comprehensive review of single-atom catalysts as agents of precise modulation.

Single-atom catalysts (SACs) present a compelling strategy to overcome the persistent challenges in lithium-sulfur batteries, such as polysulfide shuttling and sluggish redox kinetics. Their atomically dispersed nature and tunable coordination structures enable selective modulation of intermediate species and catalytic interfaces. Despite rapid progress, SAC design remains largely empirical, lacking a unified mechanistic framework. In this review, we outline a precision catalysis paradigm for SACs in lithium-sulfur systems. The discussion is organized along three core dimensions: spatial configuration, reaction pathway control, and functional integration. We summarize how coordination asymmetry, charge redistribution, and interfacial electronic coupling influence the adsorption and transformation of lithium polysulfides and Li2S. These insights are supported by spectroscopic characterization and theoretical calculations. Beyond conventional activity descriptors, we uncover structure-activity correlations involving d-band shifts, orbital hybridization, and electronic field effects. The concluded framework is further applied to sodium-sulfur, potassium-sulfur, and solid-state lithium-sulfur systems, demonstrating broad applicability. This review advances the understanding of SACs from passive adsorption sites toward programmable redox regulation. It provides conceptual and design guidance for future catalyst development based on adaptive coordination environments and data-driven optimization strategies.