Freeze-drying and hot-pressing strategy to embed two-dimensional Ti0.87O2 monolayers in commercial polypropylene films with enhanced dielectric properties

Abstract

The dielectric capacitor has been widely used in advanced electronic and electrical power systems due to its capability of ultrafast charging-discharging and ultrahigh power density. Nevertheless, its energy density is still limited by the low dielectric constant(≈ 2.2) of the commercial dielectric polypropylene (PP). The conventional enhancement strategy by embedding inorganic fillers in PP matrix is still difficult and challenging due to that PP hardly dissolves in any inorganic/organic solvent. In this work, we develop a new strategy including freeze-drying, surface functionalization, and hot-pressing to incorporate Ti_0.87O₂ monolayers in PP film. A series of uniform composited Ti_0.87O₂@PP film has been successfully fabricated with Ti_0.87O₂ content range of 0–15 wt%. The maximum dielectric constant of the as-prepared Ti_0.87O₂@PP film is 3.27 when the Ti_0.87O₂ content is 9 wt%, which is about 1.5 times higher than that of pure PP. Our study provides a feasible strategy to embed two-dimensional material into commercial PP thin-film with superior dielectric performance for practical application.