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

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., Na₃ V₂ (PO₄ )₂ O₂ F/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.