Nano-Silicon Encased in a S, N Co-doped Carbon Shells Anode Delivers High Lithium-Ion Storage Performance

• Published in: ACS sustainable chemistry & engineering Vol. 12; no. 33; pp. 12542 - 12552
• Main Authors: Ma, Xinlong, Sun, Dong, Zhang, Menglin, Wang, Meng, Ma, Zhuang, Sun, Yankun, Li, Zechen, Zheng, Fangzhi, Zhao, Kai, Yang, Yin, Lu, Changbo, Xu, Chunming, Xiao, Zhihua, Li, Yongfeng
• Format: Journal Article
• Language: English
• Published: American Chemical Society 19.08.2024
• Subjects: Lithium-ion batteries; Volume change; Si@C electrode; Liquid phase ball milling; Carbon coating
• ISSN: 2168-0485; 2168-0485
• DOI: 10.1021/acssuschemeng.4c04020

Nano-silicon (Si) integrating carbonous material has been recognized as a viable approach for restraining the intrinsic serious volume change and enhancing poor conductivity, finally resulting in improved electrochemical properties, including capacity, rate performance, and cycling life-span. Nevertheless, it remains a huge challenge via a straightforward strategy to obtain the homogeneous Si@C composite with an exceptional Li+ storage performance. Herein, novel Si integrating a S, N co-doped carbon shell and a graphite composite material (Si@C/SN@Graphite) have been prepared through combining in situ carbon coating with a liquid-phase ball milling method, in which thiourea was used as dopant, poly­(ethylene glycols) were used as carbon coating precursor, and graphite was utilized as carbon matrix. The combined effect of the S and N co-doping carbon coating layer and graphite sheet is sufficient to efficiently restrain the serious volume expansion, enhance electronic conductivity, and provide numerous Li+ storage rooms for Si anode. Furthermore, the theoretical simulation and electrochemical testing have been carried out to further demonstrate the superiority of the S, N co-doped carbon coating layer. As a result, the as-prepared Si@C/SN anode delivers a notable initial Coulombic efficiency (ICE) of 91%, high reversible capacity of 1213 mAh/g at 2 A/g within 0–1.0 V coupled with 92.8% capacity retention rate for 400 cycles. Moreover, the Si@C/SN@Graphite anode exhibits outstanding reversible capacities of 690 and 379 mAh/g at 0.05 and 1 A/g within 0–2 V along with a 90% capacity retention rate for 500 cycles. Additionally, the full cell assembled by using Si@C/SN@Graphite as anode and LiFePO4 as cathode presents reversible capacities of 176.5 and 137.9 mAh/g at 0.2 and 3 C, respectively, and considerable ICE of 92% as well as 90% capacity retention for 200 cycles. This work provides a facile and cost-effective strategy for obtaining Si@C composites with exceptional Li-ion storage capabilities in LIBs.