ZnS nanoparticles embedded in N-doped porous carbon xerogel as electrode materials for sodium-ion batteries

• Published in: Journal of alloys and compounds 2021-10, Vol.877, p.160299, Article 160299
• Main Authors: Tian, Guiying, Song, Yuanyuan, Luo, Xianlin, Zhao, Zijian, Han, Fanfan, Chen, Jiali, Huang, Huaming, Tang, Na, Dsoke, Sonia
• Format: Article
• Language: English
• Subjects: Carbon; Carbon xerogel; Coated electrodes; Coulombic efficiency; Current density; Cycles; Cycling stability; Electrochemical impedance spectroscopy; Electrode materials; Electrodes; High temperature; Metal sulfides; Nanoparticles; Photoelectrons; Polyelectrolytes; Rechargeable batteries; Sintering (powder metallurgy); Sodium-ion batteries; Sodium-ion battery; Solid electrolytes; Spectroscopic analysis; Spectrum analysis; Storage capacity; Xerogels; Zinc sulfide
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.160299

•ZnS nanoparticles embedded in N-doped porous carbon xerogel was synthesized;•N-doped carbon enhances the conductivity of the ZnS nanoparticles;•Reason for low initial Coulombic efficiency of ZnS is explained via XPS analysis;•Polymeric components in SEI layer prefers to form on the surface of loading carbon; [Display omitted] zinc sulfide (ZnS) has attracted extensive attention as an electrode material for sodium-ion batteries (SIBs) due to its high capacity and abundant resource. In order to improve the cycling stability, ZnS nanoparticles embedded in N-doped porous carbon xerogel (ZnS/N-CX) were prepared via a facile electrostatic assembly, followed by a high-temperature sintering treatment. In contrast to the retention rate of bare ZnS electrode (6.4%), the ZnS/N-CX electrode shows better capacity retention (51.8%) at a current density of 0.5 A g−1, and delivers a reversible capacity of 312 mAh g−1 at a current density of 0.1 A g−1. This is because the porous N-CX derived from polyelectrolytes can enhance the ZnS nanoparticles' conductivity during long-term cycling. Besides, X-ray diffraction analysis is used to confirm the (de)sodiation mechanism during the 1st cycle of the ZnS/N-CX electrode. In addition, X-ray photoelectron spectroscopy analysis indicates that polymeric components in the solid electrolyte interphase (SEI) prefer to form on the surface of loaded N-CX, resulting in a massive Na+ consumption and rapid decrease of initial Coulombic efficiency (CE). The analysis of electrochemical impedance spectroscopy reveals that the increase of interface resistance is suppressed in long-term cycling, with respect to the bare ZnS electrode. Therefore, these results prove that the synergistic approach of supporting/coating N-CX can be applied in the metal sulfides to achieve improved performance in terms of Na+ storage capacity.