In situ synthesis of Schiff-base polymer-derived N-doped carbon encapsulated SnSb anodes for sodium-ion batteries

Alloy anodes for sodium-ion batteries suffer from severe volume expansion. Herein, we report an innovative, energy-efficient strategy to encapsulate SnSb nanoparticles within a defect-rich, N-doped carbon shell (SnSb@N–C). Using a room-temperature in situ polymerization of a Schiff-base polymer followed by carbothermal reduction, uniform core-shell structures are achieved. The nitrogen-rich polymer skeleton serves as an ideal carbon source, effectively buffering volume changes and enhancing charge transport. Consequently, the SnSb@N–C anode exhibits outstanding cycling stability, delivering 343 mAh·g−1 after 500 cycles at 2 A·g−1. This scalable approach offers a new pathway for advanced energy storage materials.