Co/Li 2 S of chemical confinement decorated electrochemically stable Co(OH)F nanoarrays enabling dendrite-free flexible 3D Li anodes

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 12; no. 27; pp. 16491 - 16501
• Main Authors: Song, Liubin, Wang, Yixuan, Qian, Huaming, Bai, Mengxin, Chen, Qinchuan, Xiao, Minzhi, Zhao, Tingting, Xiao, Zhongliang, Wang, Jingjing, Li, Xifei
• Format: Journal Article
• Language: English
• Published: 09.07.2024
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D4TA02143F

Lithium (Li) metal is regarded as a promising anode for high-energy-density Li-ion batteries because of its high theoretical specific capacity and low potential. Unfortunately, the safety issues derived from Li dendrite formation have hindered their commercialization. Thus, fabricating a flexible, three-dimensional (3D) composite Li anode is an effective strategy to suppress Li dendrite growth. Lithiophilic nanoarrays are commonly constructed on a 3D skeleton to increase its surface area and lithiophilicity. However, the lithiophilic nanoarrays are unstable due to the conversion reaction during Li plating/stripping. Therefore, designing composite nanoarrays with an electrochemically stable inner core and a lithiophilic outer shell is conducive to providing a large surface area and promoting uniform Li deposition. Herein, CoS 2 shell–Co(OH)F core composite nanowire arrays were prepared on carbon cloth (CoS 2 –Co(OH)F/CC) to fabricate a flexible 3D composite Li anode (Li@CoS 2 –Co(OH)F/CC), in which the electrochemically stable Co(OH)F core ensures the stability of the nanoarray and the lithiophilic CoS 2 shell facilitates uniform Li adsorption. Moreover, the Co/Li 2 S configuration derived from the lithiation of CoS 2 could promote homogeneous Li deposition, in which the lithiophilic Li 2 S phase and electron-conductive Co phase jointly facilitate uniform Li nucleation and charge transfer. Consequently, the symmetric cells and full cells paired with a LiFePO 4 (LFP) cathode based on the flexible Li@CoS 2 –Co(OH)F/CC anode presented superior cycling stability.