CNTs-intertwined and N-doped porous carbon wrapped silicon anode for high performance lithium-ion batteries

• Published in: Journal of alloys and compounds 2021-10, Vol.877, p.160240, Article 160240
• Main Authors: Qiu, Yiwei, Zhang, Chenying, Zhang, Chengkun, Xie, Qingshui, Qiao, Zhensong, Zeng, Xiangzhe, Xu, Wanjie, Zheng, Hongfei, Li, Shuai, Lin, Jie, Peng, Dong-Liang
• Format: Article
• Language: English
• Subjects: Anodes; Bimetals; Carbon; Carbon modification; Cobalt silicide; Competitive materials; Electrical resistivity; Electrochemical analysis; Electrode materials; Graphitization; Heat treatment; Lithium; Lithium storage properties; Lithium-ion batteries; Nanoparticles; Porous structure; Rechargeable batteries; Silicon; Silicon anode; Structural hierarchy; Structural stability; ZnCo-ZIF
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.160240

•CNTs and N-doped carbon decoration can enhance electronic conductivity of Si-based anode.•CoSi2 can improve the structural stability of Si-based anode.•The introduced Co can catalyze the graphitization of carbon shell.•The designed Si-based anode delivers enhanced electrochemical properties. [Display omitted] Silicon is evaluated as a competitive lithium-ion batteries anode material by virtue of its ultrahigh specific capacity and relatively low discharge potential. However, the large volume change during lithiation/delithiation processes, and the low intrinsic electric conductivity have seriously impeded its widespread practical application. Herein, silicon nanoparticles (SiNPs) coated with CNTs-intertwined N-doped porous carbon (NPC) are prepared via a facile solution-phase method, followed by thermal annealing treatment. In this hierarchical structure, the bimetallic ZIF-derived porous carbon can shorten the migration channels of Li+ and electrons. Moreover, the formed Co nanoparticles can not only catalyze the graphitization of carbon, but also propel in-situ growth of CNTs to constitute a 3D interconnected conductive network, thereby improving the electrochemical performance. Benefiting from the unique structure, the as-prepared Si@CoSi2/Co-NPC@CNTs electrode exhibits superior electrochemical performance of 1191 mAh g−1 at 0.5 A g−1 after 200 cycles. Meanwhile, the electrode also shows excellent rate capability of 930 mAh g−1 even at a high current density of 6 A g−1. This work provides a new strategy to design exceptionally high electrical conductivity and structure stability of Si-based anode materials.