Hollow Nanostructure and Electronic Structure Synergistic Modulation of Metal Sulfide Anodes for Sodium–Ion Batteries: Recent Progress and Perspectives

Sodium-ion batteries are promising alternatives to lithium-ion batteries for large-scale energy storage, benefiting from abundant, low-cost sodium resources. Metal sulfides are attractive anode candidates due to diverse compositions, ultrahigh theoretical capacity and favorable electrochemical properties. However, their poor intrinsic conductivity, sluggish reaction kinetics and severe cycling-induced volume expansion greatly restrict practical development. Constructing hierarchical hollow architectures and regulating electronic structures are effective solutions. Hierarchical hollow structures offer large specific surface areas and shortened charge transport paths to mitigate volume variation and stabilize cycling. Electronic modulation improves conductivity, accelerates ion/electron transport and creates more active sites. The synergistic regulation of hierarchical hollow nanostructure and electronic structure is critical to boost overall electrochemical performance, yet its underlying mechanism lacks systematic understanding. This article reviews the latest advances in the design and synthesis of various hierarchical hollow structures and electronic structure-regulated metal sulfide-based anode materials, and focuses on analyzing the influence laws of the coordinated engineering of hierarchical structures and electronic structures on the sodium storage performance. It is expected to provide ideas for the innovative research and development of new battery electrode materials.