A Universal Cross‐Synthetic Strategy for Sub‐10 nm Metal‐Based Composites with Excellent Ion Storage Kinetics

Abstract The sub‐10 nm metal‐based nanomaterials (SMNs) show great potential for the electrochemical energy storage field. However, their ion storage capacity and stability suffer from severe agglomeration and interface problems. Herein, a universal strategy is reported to synthesize a wide range of SMNs (e.g., metal, nitride, oxide, and sulfides) embedded in free‐standing carbon foam (SMN/FC‐F) composite electrodes by crossing the interfacial confinement of NaCl self‐assembly with the thermal‐mechanical coupling of powder metallurgy. The pressure‐enhanced NaCl self‐assembly interfacial confinement is greatly beneficial to preventing SMN agglomeration and promoting SMNs embedded in FC‐F which originate from the welding of carbon nanosheets. They are confirmed via a series of advanced characterizations including X‐ray photoelectron spectroscopy, and spherical aberration‐corrected scanning transmission electron microscopy, with theoretical computations. Benefiting from the unique structure, SMNs/FC‐F delivers ultrafast and stable ion‐storage kinetics. As a proof‐of‐concept demonstration, the MoS₂/FC‐F shows excellent ion storage kinetics and superior long‐term cycling performance for ion storage (e.g., Na₃V₂(PO₄)₂O₂F/C//MoS₂/FC‐F sodium‐ion batteries exhibit a high reversible capacity of 185 mAh g⁻¹ at 0.5 A g⁻¹ with a decay rate of 0.05% per cycle.). This work provides a new opportunity to design and fabricate promising SMN‐based free‐standing working electrodes for electrochemical energy storage and conversion applications.