Tailored SnAl-Cu6Sn5 composite with hierarchical porous architecture for enhanced sodium storage

Tin (Sn) stands as a promising anode for sodium-ion batteries due to its high theoretical capacity, yet it suffers from severe volume changes during cycling. This work develops a novel SnAl-Cu 6 Sn 5 composite through a rational dealloying strategy, featuring a unique 3D continuous bimodal porous structure that effectively mitigates mechanical stress during Na⁺ insertion/extraction. The incorporated Cu and Al components act as the bimetallic conductive network and thus benefit the electron transfer. Remarkably, the anode delivers an initial capacity of 432.6 mAh g −1 at 1 A g −1 and retains 291.4 mAh g −1 after 1000 cycles with the capacity retention of 67.4%. Furthermore, the Na 3 V 2 (PO 4 ) 3 //SnAl-Cu 6 Sn 5 full cell demonstrated excellent rate performance and cycling stability, maintaining 96.7% of its initial capacity after 100 cycles at 1 C. These findings provide important methodological guidance for the application of tin-based materials as high performance anodes in sodium-ion batteries.