Enabling Low‐Temperature Fast‐Charging Anode‐Free Sodium Metal Batteries: A Synergistic Design of Electrolyte Solvation and Current Collector Interface

Abstract

Anode‐free sodium metal batteries (AFSMBs) promise ultrahigh energy density (>350 Wh kg −1 ) and low cost, yet their operation under low‐temperature and fast‐charging conditions is critically hindered by limited sodium inventory and sluggish interfacial kinetics. This conflict creates a “stability paradox”: the pursuit of high energy density amplifies interfacial instability, leading to inhomogeneous sodium deposition and rapid capacity decay. This review systematically analyzes AFSMB failure mechanisms under extreme conditions and demonstrates that overcoming these bottlenecks requires integrated co‐design across four synergistic domains: (1) engineering electrolyte solvation structures (weakly solvating, high‐concentration, and high‐entropy designs) to lower the desolvation barrier and stabilize the solid–electrolyte interphase; (2) tailoring current collector interfaces with sodiophilic coatings or three‐dimensional architectures to guide uniform sodium deposition; (3) incorporating rational pre‐sodiation strategies to compensate irreversible sodium loss; and (4) leveraging artificial intelligence and molecular simulations for data‐driven electrolyte screening. We critically assess the trade‐offs of each strategy and provide a forward‐looking perspective on reversible sodium compensation, multi‐scale AI platforms, and full‐cell integration. This review offers a roadmap for developing practical, wide‐temperature‐range, high‐energy‐density AFSMBs, with recent pouch cells already demonstrating >200 Wh kg −1 and stable cycling from −40°C to 60°C.