Antimony (Sb) is regarded as an attractive anode material for sodium-ion batteries (SIBs) due to its high theoretical capacity of 660 mAh g–1. Combining Sb with carbonaceous materials has been considered as an effective way to resolve the serious volume expansion issues. Sb/C composites mainly consist of two types, that is, Sb confined inside a carbon matrix and Sb deposited on the surface of a carbon matrix, and both have shown superior sodium storage performance. However, which structure is more beneficial for achieving high electrochemical performance is still unclear. In this work, peapod-like Sb@C and corn-like C@Sb nanotubes are synthesized via a nanoconfined galvanic replacement reaction and used as model materials for sodium storage to explore the above issue. When evaluated as anode materials for SIBs, the peapod-like Sb@C shows a higher rate capability and a significantly better long-term cycling stability compared to those of the corn-like C@Sb. Electrochemical analysis reveals that the peapod-like Sb@C exhibits faster Na+ and electron transport kinetics and higher proportions of surface capacitive contributions. These results demonstrate the structural superiority of the nanoconfined structure and provide valuable information for the rational design and construction of Sb-based anode materials for high-performance electrochemical energy storage.

Antimony is an attractive anode material for sodium‐ion batteries (SIBs) owing to its high theoretical capacity and appropriate sodiation potential. However, its practical application is severely impeded by its poor cycling stability caused by dramatic volumetric variations during sodium uptake and release processes. Here, to circumvent this obstacle, Sb@C@TiO2 triple‐shell nanoboxes (TSNBs) are synthesized through a template‐engaged galvanic replacement approach. The TSNB structure consists of an inner Sb hollow nanobox protected by a conductive carbon middle shell and a TiO2‐nanosheet‐constructed outer shell. This structure offers dual protection to the inner Sb and enough room to accommodate volume expansion, thus promoting the structural integrity of the electrode and the formation of a stable solid–electrolyte interface film. Benefiting from the rational structural design and synergistic effects of Sb, carbon, and TiO2, the Sb@C@TiO2 electrode exhibits superior rate performance (212 mAh g−1 at 10 A g−1) and outstanding long‐term cycling stability (193 mAh g−1 at 1 A g−1 after 4000 cycles). Moreover, a full cell assembled with a configuration of Sb@C@TiO2//Na3(VOPO4)2F displays a high output voltage of 2.8 V and a high energy density of 179 Wh kg−1, revealing the great promise of Sb@C@TiO2 TSNBs as the electrode in SIBs.