Xiao Zhang, Chunling Zhu, Ziqian Ma, Yujin Chen
Metal single-atom absorbers (M-SAAs) are redefining the frontier of electromagnetic wave (EMW) absorption by exploiting atomically dispersed sites, programmable coordination environments, and strong metal-support interactions. Unlike conventional absorbers, M-SAAs deliver extraordinary dielectric loss efficiency and broadband absorption, thereby opening new avenues for lightweight, wideband, and adaptive EM protection. Despite these advances, the intrinsic dielectric loss mechanisms and the structure–property correlations between coordination environments and dielectric loss remain poorly understood. This review provides the first atomic-scale mechanistic analysis of M-SAAs, offering a comprehensive dissection of their polarization loss mechanisms, a systematic summary of regulation strategies involving metal species, coordination environments, loading densities, and support architectures, and a fundamental elucidation of the underlying principles governing their dielectric performance. Building on these insights, we propose a forward-looking roadmap encompassing scalable and cost-effective synthesis, exploration of non‑carbon supports, multidimensional structural engineering, and the creation of intelligent, dynamically tunable, and programmable absorption systems. We further outline the key challenges and emerging opportunities of M-SAAs in extreme-environment protection, adaptive sensing, and stealth technologies. This work provides both a theoretical foundation and a visionary outlook for accelerating disruptive breakthroughs in EM compatibility and radiation mitigation.