Delicate Co‐Control of Shell Structure and Sulfur Vacancies in Interlayer‐Expanded Tungsten Disulfide Hollow Sphere for Fast and Stable Sodium Storage

Abstract Hollow multishelled structure (HoMS) is a promising multi‐functional platform for energy storage, owing to its unique temporal‐spatial ordering property and buffering function. Accurate co‐control of its multiscale structures may bring fascinating properties and new opportunities, which is highly desired yet rarely achieved due to the challenging synthesis. Herein, a sequential sulfidation and etching approach is developed to achieve the delicate co‐control over both molecular‐ and nano‐/micro‐scale structure of WS 2− x HoMS. Typically, sextuple‐shelled WS 2− x HoMS with abundant sulfur vacancies and expanded‐interlayer spacing is obtained from triple‐shelled WO 3 HoMS. By further coating with nitrogen‐doped carbon, WS 2− x HoMS maintains a reversible capacity of 241.7 mAh g −1 at 5 A g −1 after 1000 cycles for sodium storage, which is superior to the previously reported results. Mechanism analyses reveal that HoMS provides good electrode–electrolyte contact and plentiful sodium storage sites as well as an effective buffer of the stress/strain during cycling; sulfur vacancy and expanded interlayer of WS 2− x enhance ion diffusion kinetics; carbon coating improves the electron conductivity and benefits the structural stability. This finding offers prospects for realizing practical fast‐charging, high‐energy, and long‐cycling sodium storage.