Improving electric insulation characteristics of PVA/V2C MXene composite high-dielectric-constant films by blending cellulose

Abstract

Polymer/conductor composite dielectrics easily have high permittivity, high conductivity, and high dielectric loss, limiting large increase of energy storage density in them. The relationship between high permittivity and low conductivity is coordinated to achieve high energy density. In this study, polyvinyl alcohol (PVA)/V2C MXene/cellulose ternary composites with high permittivity and low dielectric loss were prepared. Due to good water solubility of PVA and high water dispersibility of V2C, PVA and V2C have good interfacial compatibility. That reduces the interface electric leakage conductance, which is conducive to the lower conductivity and dielectric loss in the composite materials. The high interfacial polarization between PVA and V2C improves the dielectric response of the composite materials, improving the permittivity of the composite materials. Compared with binary PVA/V2C composites, ternary PVA/V2C/cellulose composite materials use the high insulation of cellulose filler to increase the insulation of composites. Thus, the conductivity and dielectric loss are reduced in ternary composites. Good synergy of conductive V2C and insulating cellulose fillers is important to obtaining the balance of high dielectric response and high insulation trait in ternary composites. Best ternary composite with 6 wt% V2C has a high permittivity of ca. 40, low dielectric loss of ca. 0.25 at 100 Hz, and high breakdown strength of ca. 40 MV m−1. This work enables a facile preparation of promising composites for dielectric energy storage. • Novel ternary composite dielectric films with V 2 C MXene and cellulose were fabricated. • Good synergy of V 2 C and cellulose can lead to optimization of overall electric properties. • This work might provide ideas for preparing bio-dielectric materials employing cellulose.