In situ growth of metallic 1T-WS2 nanoislands on single-walled carbon nanotube films for improved electrochemical performance

Abstract

Layered tungsten disulfide (WS₂) is a potential electrode material for electric double layer capacitance (EDLC) and hydrogen evolution reaction (HER). However, the electrochemical performance of WS₂ has been hindered by the semiconducting nature and poor active sites. Herein, we have demonstrated a bottom-up hydrothermal approach to fabricate metallic 1T-WS₂ nanoislands in situ grown on flexible single-walled carbon nanotube nonwovens (1T-WS₂@SWCNT). The robust hybrids with a tight interface possess nanoscopic few-layered WS₂ pieces with an abundance of exposed sites, along with a unique woven-architecture originating from the high conductive carbon nanotube network. The in situ-growing enhanced interface between metallic WS₂ nanoislands and SWCNTs provides a relatively strong electrical coupling integrity, which facilitates charge transfer during electrochemical reactions. The merits of rich active sites, excellent conductivity and well bonding-interactions are significantly beneficial to improve the electrochemical performance. Particularly, in contrast to the pure material, the as-obtained hybrids are found to exhibit higher EDLC capacity (226 mF cm⁻²), almost 646-fold higher than pure 1T-WS₂, smaller Tafel slope (57 mV per decade) and lower HER overpotential (∼25 mV) than any WS₂-based materials reported so far.