A Precursor Design Principle for Archipelagic Hard‐Carbon Structural Evolution Through Cohesion–Solvation Regulation of Asphaltene Molecular Heterogeneity

Sodium‐ion batteries are central to the development of affordable electrochemical storage for renewable energy integration. Yet hard‐carbon anode design lacks a precursor‐level principle linking molecular assembly in chemically heterogeneous feedstocks to oxidative stabilization and closed‐pore formation. Here we establish a precursor‐level cohesion‐solvation design principle for regulating molecular selection and assembly in heterogeneous aromatic feedstocks. Toluene‐fractionated asphaltene precursors undergo oxidative crosslinking, redirecting carbonization from continuous coke‐like growth toward separated turbostratic domains and confined closed pores. A hard‐carbon performance screening index (HPSI) quantifies structural and electrochemical performance, while density functional theory (DFT) reveals stronger Na affinity and lower migration barriers in defect‐engineered carbon galleries. The solvent‐selected AHC‐80‐1400 delivers 400.1 mAh g −1 at 0.05 A g −1 with 87.7% ICE and retains 92.3% capacity after 10 000 cycles, while sustaining wide‐temperature sodium storage with 91.8% and 90.4% retention at −20°C and 50°C, respectively. At scale, a 10‐kg batch enables a 1.18 Ah NFM||AHC‐80‐1400 pouch cell, delivering 163.3 Wh kg −1 and 95.5% retention after 700 cycles. A cradle‐to‐gate life‐cycle assessment (LCA) shows that AHC‐80‐1400 production reduces climate‐change impact by 33.7% relative to Commercial HC. These findings establish precursor‐stage molecular selection as a design principle for harnessing feedstock heterogeneity to control carbonization trajectories and electrochemical function.