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A Restacking Inhibited Carbonization Pathway for Graphitization-Prone Precursors Toward Long-Life Sodium-Ion
Yuhan Liu1, Hao Yang1, Qianxun Li1
1Shenzhen Key Laboratory of Interfacial Science and Engineering of Materials, Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
None:
Theory-guided design of hard carbon anode from graphitization-prone precursors remains challenging because oxidation and carbonization routes lack mechanisms to selectively disrupt ordered π-π stacking while preserving structural integrity during carbonation for performance. We propose an intrinsic heteroatom-assisted site-preferential oxidation mechanism that enables framework disruption and kinetically inhibits restacking during carbonization of petroleum asphaltenes rich in heteroatoms. Electronic inhomogeneity of nitric acid makes its acid-derived radicals preferentially anchor on heteroatom-modified sites, inducing steric hindrance and oxidation-guided pore evolution that yields turbostratic hard carbon with expanded interlayer spacing and closed pores. Operando characterization and density functional theory (DFT) calculations identified this heteroatom-mediated localized reactivity as the origin of suppressed graphitization and enhanced sodium-storage kinetics. The resulting material delivers a high initial Coulombic efficiency (ICE) of 89.7% and a reversible capacity of 404.1 mAh g-1, with a 93.2% capacity retention after 2200 cycles, outperforming most reported pitch-derived hard carbons. Practical applicability is demonstrated in a 1.2 Ah pouch-cell, while cradle-to-gate life cycle assessment (LCA) indicates substantially reduced environmental impacts as compared with representative commercial hard carbons. Beyond offering a generalizable strategy for converting low-quality thermoplastic carbon sources into durable sodium-ion battery anode materials, this study also offers mechanistic insights into selective carbonization pathways.

