Low‐Defect Carbon Host Enabling Robust Zero‐Excess Sodium Metal Batteries Without Presodiation

ABSTRACT Zero‐excess Na metal batteries offer transformative potential for future energy‐dense, low‐cost energy storage, yet face aggravated cycling/rate deterioration due to irrecoverable Na + depletion. While state‐of‐the‐art sodiophilic carbon hosts enable highly reversible plating/stripping with impressive stability, they rely heavily on artificial presodiation to offset irreversible Na + consumption by sodiophilic defective sites, a fundamental barrier to practical zero‐excess configurations. Here, we propose a low‐defect carbon host (LDCH) that eliminates the need for presodiation while maintaining exceptional sodiophilicity even at high charging rates. Mechanistic studies show that LDCH operates primarily through a low‐potential plateau storage mechanism, which enhances Na affinity, reduces the nucleation barrier, and suppresses irreversible Na + loss by 4.67 times compared to defective counterparts. Crucially, LDCH circumvents the sodiophobic transition observed in defect‐rich carbon counterparts under fast‐charging operation, attributed to hidden sodiophilic seed sites near 0 V with rapid kinetics. The resulting zero‐excess Na metal battery achieves an unprecedented 84.6% initial Coulombic efficiency without pre‐cycling (vs. 66.1% for defective hosts), delivers an energy density of 281.1 Wh kg −1 , 75% capacity retention after 110 cycles and 5 C fast charging, representing a breaking combination of energy/durability/rate. This low‐defect engineering strategy redefines carbon host design principle, resolving the long‐standing presodiation dilemma in zero‐excess sodium metal batteries.