High-Energy Ball Milling Promoted Sulfur Immobilization for Constructing High-Performance Na-Storage Carbon Anodes

Abstract

Sulfur (S) doping is an effective method for constructing highperformance carbon anodes for sodium-ion batteries. However, traditional designs of S-doped carbon often exhibit low initial Coulombic efficiency (ICE), poor rate capability, and impoverished cycle performance, limiting their practical applications. This study proposes an innovative design strategy to fabricate Sdoped carbon using sulfonated sugar molecules as precursors via high-energy ball milling. The results show that the high-energy ball milling can immobilize S for sulfonated sugar molecules by modulating the chemical state of S atoms, thereby creating a S-rich carbon framework with a doping level of 15.5 wt %. In addition, the S atoms are present mainly in the form of C−S bonds, facilitating a stable electrochemical reaction; meanwhile, S atoms expand the spacing between carbon layers and contribute sufficient capacitance-type Na-storage sites. Consequently, the S-doped carbon exhibits a large capacity (>600 mAh g −1 ), a high ICE (>90%), superior cycling stability (490 mAh g −1 after 1100 cycles at 5 A g −1 ), and outstanding rate performance (420 mAh g −1 at a high current density of 50 A g −1 ). Such excellent Na-storage properties of S-doped carbon have rarely been reported in the literatures before.

FeSe2 Graphite Intercalation Compound as Anode Materials for Sodium Ion Batteries

“…After ball-milling treatment, the electrochemical performance of the material can be significantly improved. , Figures d and S6 exhibit the initial three cycle charge/discharge curves of FeSe 2 -GIC and FeSe 2 -GIC-BM at 0.1 A g –1 . The FeSe 2 -GIC-BM shows a reversible capacity of 530 mA h g –1 , while FeSe 2 -GIC shows a reversible capacity of 394.4 mA h g –1 at a current density of 0.1 A g –1 ; in contrast, the FeSe 2 -GIC-BM has a higher slope capacity than the FeSe 2 -GIC in the voltage range of 0.01–1.5 V. This can be attributed to the adsorption of sodium ions at the defect site and the subsequent filling of the voids.…”