• Hollow carbon spheres (HCSs) effectively mitigate polysulfide shuttling, volume expansion, and poor conductivity in Na-S and K-S batteries.
• HCSs with controllable structure and composition enhance sulfur immobilization and electrochemical performance.
• Synthesis methods and composite strategies for HCSs/sulfur are systematically reviewed.
• Future prospects highlight HCSs as promising materials for advanced metal-sulfur batteries.