Hydrogen-enriched water for mild graphite functionalization to enhance Li+ storage

초록

Although graphite remains the dominant negative electrode material for lithium-ion batteries, its theoretical capacity (372 mAh g- 1) limits its applicability in high-energy systems. Herein, we introduce a mild and previously unexplored method for the surface functionalization of graphite using hydrogen-enriched water (HW). HW treatment induced interlayer expansion, defect formation, and partial amorphization while preserving the graphitic framework, as confirmed by X-ray diffraction, Raman spectroscopy, and electron microscopy. Nitrogen sorption analysis revealed the development of hierarchical porosity, which facilitated Li+ diffusion. Electrochemical measurements showed consistent discharge-capacity increases, which reached 383 mAh g- 1, along with an improved rate capability and reduced interfacial resistance. Density functional theory calculations suggested that HW-derived H2 and OH- functionalities modulated the charge distribution, lowered the Li+ diffusion barriers, and enhanced the Li+ adsorption. These findings highlighted the benefit of HW-assisted surface engineering as a simple, sustainable, and scalable strategy for enhancing the Li+ storage performance of graphite-based negative electrodes.

키워드