Understanding the improved performance of sulfur‐doped interconnected carbon microspheres for Na‐ion storage

• Main Authors: Xinran Yuan, Siming Chen, Jinliang Li, Junpeng Xie, Genghua Yan, Botian Liu, Xibo Li, Rui Li, Likun Pan, Wenjie Mai
• Format: Article
• Language: English
• Published: Wiley 2021-08-01
• Series: Carbon Energy
• Subjects: electrochemical enhancement mechanism; electrochemical reaction; Na‐ion batteries; sulfur‐doped interconnected carbon microspheres
• Online Access: https://doi.org/10.1002/cey2.98

Abstract As one of the low‐cost energy storage systems, Na‐ion batteries (NIBs) have received tremendous attention. However, the performance of current anode materials still cannot meet the requirements of NIBs. In our work, we obtain sulfur‐doped interconnected carbon microspheres (S‐CSs) via a simple hydrothermal method and subsequent sulfurizing treatment. Our S‐CSs exhibit an ultrahigh reversible capacity of 520 mAh g–1 at 100 mA g–1 after 50 cycles and an excellent rate capability of 257 mAh g–1, even at a high current density of 2 A g–1. The density functional theory calculations demonstrate that sulfur doping in carbon favors the adsorption of Na atom during the sodiation process, which is accountable for the performance enhancement. Furthermore, we also utilize operando Raman spectroscopy to analyze the electrochemical reaction of our S‐CSs, which further highlights the sulfur doping in improving Na‐ion storage performance.