• A novel liquid-phase pulsed laser irradiation followed by solvothermal reaction produces Bi nanocrystals as small as 2 nm, the smallest reported for Bi/C composites.
• Strong Bi—O—C covalent bonds between Bi and rGO enhance interface contact, suppress aggregation, and facilitate ion/electron transport.
• The Bi-rGO-2 anode delivers a high reversible capacity of 586.7 mAh g−1 over 500 cycles, nearly double that of bulk Bi/rGO composites.
• Theoretical and kinetic analyses reveal that small Bi particle sizes increase binding energy and accelerate Li+ diffusion, enabling superior lithium storage.