Low-crystallinity tungsten disulfide construction by in-situ confinement effect enables ultrastable sodium-ion storage

• Published in: Journal of alloys and compounds 2022-04, Vol.900, p.163518, Article 163518
• Main Authors: Mo, Lulu, Gao, Mingyu, Zhou, Gangyong, Zong, Wei, Chen, Ai-Long, Fan, Xiaoshan, Miao, Yue-E, Liu, Tianxi
• Format: Article
• Language: English
• Subjects: Anodes; Carbon fibers; Carbon nanofibers; Confinement; Crystal defects; Crystal structure; Crystallinity; Cycling stability; Diffusion length; Electrospinning; Heat treatment; Ion diffusion; Ion storage; Low conductivity; Low-crystallinity WS2; Nanofibers; Nanostructure; Polyacrylonitrile; Sodium; Sodium-ion batteries; Structural stability; Tungsten disulfide; Ultrafines
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.163518

•Low-crystallinity WS2 in carbon nanofiber (WS2-CNF) composites are prepared through in-situ confinement effect.•The WS2-CNF composite presents fast electrochemical reaction kinetics and excellent structural stability.•The WS2-CNF electrode exhibits an ultralong cycling life in sodium-ion batteries. [Display omitted] As a typical metal sulfide, tungsten disulfide (WS2) with high theoretical capacity has attracted significant attention as the anode for sodium-ion batteries (SIBs). However, WS2 bulk material usually displays poor rate performance and fast capacity fading in practical applications due to its low conductivity and structural instability. Herein, we propose an in-situ confinement strategy for synthesizing low-crystallinity and ultrafine WS2 nanosheets within carbon nanofibers (WS2-CNF) by the simple heat treatment of electrospun polyacrylonitrile/ammonium tetrathiotungstate (PAN/(NH4)2WS4) nanofibers. The low-crystallinity structure of WS2 with ultrasmall size and rich defects can greatly reduce the volume change and shorten the ion diffusion length. WS2 nanosheets are confined in the CNF matrix, which is capable of effectively improving its electronic conductivity and structural stability. Based on these advantages, the WS2-CNF composite electrode demonstrates fast and ultrastable Na+ storage performance with a high capacity of 182 mAh g–1 after 6000 cycles at 5.0 A g−1. Therefore, this work provides a simple and facile strategy for developing high-performance WS2 anodes for SIBs.