Compact Solvation Enables Sub‐Minute Sodium‐Ion Storage: A Data‐Driven Perspective

ABSTRACT Extremely fast charging (XFC) of batteries holds significant importance in the era of intelligent technologies, yet the intricate role of electrolyte properties in determining XFC behavior remains obscure. Furthermore, conventional theories and in situ characterization techniques fails to elucidate electrochemical behaviors under sub‐minute‐level charging conditions. Herein, we report a data‐driven approach for analyzing the effect of each independent physical and solvation property on sub‐minute‐level sodium‐ion storage behavior. Causal graph analysis reveals that the size of the solvation clusters shows the strongest negative correlation with ultrafast Na + storage in graphite. The optimized compact solvation electrolyte demonstrates an astonishing extreme current density of 250 A g −1 (corresponding to a power density of 46.78 kW kg −1 graphite ) and an unprecedented cycle life of 100 000 cycles. Most notably, the graphite||Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 full batteries achieve stable sub‐minute‐level charging and discharging, exhibiting ultrahigh rate capabilities (up to 200 C, ∼3.4 s per charge) and ultra‐stable cycle performance (24 000 cycles at 50 C, ∼29 s per charge). This work provides a promising pathway for the development of XFC battery, pioneering an innovative assessment strategy for next‐generation electrolytes.