Engineering Pseudo-Graphite-Dominated Hard Carbon as Anode for Sodium-Ion Batteries
Hesheng Yu, Xi Liu, Ziheng Zhang, Yu Wu, Daiqian Chen, Jinri Huang, Yuping Wu, Yuanfu Chen, Jiarui He
Abstract
It remains challenging to develop hard carbon that simultaneously meets the requirements of initial Coulombic efficiency (ICE) and capacity for practical sodium-ion batteries (SIBs). Herein, we present a carbon nanotubes (CNT)-templating strategy to engineer pseudo-graphitic domains within hard carbon (PG-HC), resulting in enhanced graphitization extent, optimized closed pores, expanded interlayer spacing, and enriched ultramicropores. These merits enable PG-HC to have decreased defect densities and irreversible side reactions as well as enhanced sodium storage sites and transport kinetics, thus delivering an ICE of 94%, a reversible capacity of 426 mAh g –1, and long-term cycling stability. A “rich ultramicropore adsorption–expanded interlayer insertion–closed pore filling” mechanism is elucidated via in situ XRD and Raman characterizations. This work establishes a direct correlation among structural modulation, performance enhancement, and the sodium storage mechanism of hard carbon, offering valuable insights for the development of SIBs.