Sequential Li-intercalation exfoliation enables high-purity NbSe2 with enhanced electrical and thermal performance

Abstract

This study presents a scalable sequential lithium intercalation exfoliation strategy that significantly enhances the purity, crystallinity, and electrical performance of two-dimensional NbSe₂ synthesized from powder precursors. While conventional single-step Li-intercalation methods often lead to partial exfoliation, surface oxidation, and compromised conductivity, the proposed sequential approach enables the progressive removal of oxide-rich residues and promotes the formation of uniform, defect-minimized NbSe₂ nanosheets. The resulting material exhibits substantially reduced surface oxide content, improved layer alignment, and achieves up to a ∼6.5× reduction in electrical resistance with stable performance over 14 days under ambient conditions. In particular, the purified NbSe₂ thin films demonstrate a rapid temperature rise to ∼150 °C within ∼40 s and spatially uniform Joule-heating behavior without localized hotspots, indicating strong potential for use in flexible and reliable thermal management components. Beyond NbSe₂, this methodology offers a generalizable route for producing high-quality, conductive TMDC films, thereby addressing persistent challenges in powder-based 2D material processing and supporting their potential integration into advanced nanoelectronic, optoelectronic, and energy-related technologies.