A Restacking Inhibited Carbonization Pathway for Graphitization-Prone Precursors Toward Long-Life Sodium-Ion Batteries.

Abstract

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.