Rational Sulfur Vacancy Design Enhances the Electrochemical and Nonlinear Optical Properties of V 2 CT x /WS 2

Abstract

ABSTRACT The concurrent optimization of electrochemical energy storage and third‐order nonlinear optical (NLO) performance within a single material system remains a fundamental challenge. Here, V 2 CT x /WS 2 composites were fabricated via a solvothermal method on carbon cloth substrates, and (V 2 CT x /WS 2 ) x /PMMA were prepared for optical measurements. Interfacial interactions between V 2 CT x surface functional groups and WS 2 promote the formation of sulfur vacancies and interfacial charge redistribution during compositing. The enlarged interlayer spacing, three‐dimensional WS 2 nanoflower architecture, and defect‐rich structure collectively increase accessible active sites and facilitate charge transport. The V 2 CT x /WS 2 electrode delivers a specific capacity of 2251.95 F·g −1 at 1 A·g −1 , retaining 94.80% of its initial capacity after 10 000 cycles. The assembled supercapacitor achieves an energy density of 47.93 Wh·kg −1 at a power density of 983.45 W·kg −1 . For NLO performance, the (V 2 CT x /WS 2 ) 8 /PMMA sample exhibits a nonlinear absorption coefficient β of 232 cm·GW −1 , a nonlinear refraction coefficient γ of −9.29 × 10 −4 cm 2 ·GW −1 , and an optical limiting threshold of 1.09 J·cm −2 . The results demonstrate that V 2 CT x /WS 2 exhibits excellent electrochemical and NLO properties through composite structure design and defect engineering.