Nano FeSb<sub>2</sub>S<sub>4</sub> Anchored on Exfoliated Graphite for Sodium-Ion Battery Anode via a Two-Step Fabrication
Peng Wang, Yi‐hong Ding, Ying‐Hao Chu, Xinxin Zhu, Jie Lin, Li‐Xiong Shao, Tianbiao Zeng
Abstract
FeSb 2 S 4 is considered a potential anode material of sodium-ion batteries (SIBs) due to the high theoretical capacity (877 mAh g –1 ) and fast Na + diffusion kinetics. Synthesis of the FeSb 2 S 4 -based anode via a simple strategy is essential for practical applications. In this study, nano FeSb 2 S 4 anchored on exfoliated graphite (FeSb 2 S 4 -G) was fabricated via a two-step strategy: heat treatment of commercial FeS+Sb 2 S 3 powder and then ball-milling with commercial graphite. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations reveal that the pulverized nano FeSb 2 S 4 and exfoliated graphite establish the chemical bonds, which is very advantageous to boost the charge/discharge reversibility. As-prepared FeSb 2 S 4 -G delivered 577 mAh g –1 in the second cycle under 100 mA g –1 and kept 385 mAh g –1 in the 70th cycle; the cycling stability surpassed bulk FeSb 2 S 4 (662 mAh g –1 in the 2nd cycle, 109 mAh g –1 in the 70th cycle). Considering only two steps of the synthesis processes, this work presents a viable strategy for fabricating high-performance FeSb 2 S 4 -based SIB anode materials.