• Sodium ion batteries (SIBs) are a promising, cost-effective alternative to lithium-ion batteries due to abundant sodium reserves.
• Anode materials for SIBs include carbon-based, metallic, and organic types, operating via intercalation, alloying, or conversion mechanisms.
• Key challenges for SIB anodes include slow Na+ diffusion, large volume changes, and unstable solid electrolyte interface (SEI), addressed by doping, coating, and structural modifications.
• This review provides a comprehensive overview of anode development, highlighting strategies to improve initial coulombic efficiency, cycling stability, and low potential plateaus.