Effects of ultralow concentration MXene (nano-Ti3C2Tx) on the electric and physical properties of ternary polyvinyl alcohol composites

Abstract

High-dielectric-constant (high-κ) fillers are embedded in polymer materials to improve the dielectric constant of polymer and form high-κ composites for the latest generation of energy storage devices. However, the addition of high-κ fillers will introduce interface polarization and cause space charge accumulations that will increase dielectric loss and reduce breakdown strength. Herein introduces a conductive MXene(nano-Ti3C2Tx) with high surface area to remarkably suppress space charge in polyvinyl alcohol (PVA) matrix. A ternary PVA composite with high dielectric constant and low dielectric loss is formed by doping with ultralow concentration MXene and soluble ferroelectric [Hdabco]ClO4 (TEDA.C) via solution mixing. The space charge suppression capability of MXene sharply reduces the dielectric loss of 1M@1788PVA and 5M@1788PVA (PVA with 0.0001 wt.% and 0.0005 wt.% MXene) at low frequency (0.1−10 Hz). By comparing the activation energy of dielectric relaxation (Ea) and breakdown strength (BDS) under AC electric field between pure PVA and PVA composites, ultralow concentration MXene declines the Ea of 1M@1788PVA and 5M@1788PVA by 26.8 % and 60.9 %, and effectively improves the BDS of 1M@1788PVA and 1M5T@1788PVA (PVA with 0.0001 wt.% MXene and 4.7 wt.% TEDA.C) by 3%. The addition of ultralow concentration MXene and TEDA.C bring 5M5T@1788PVA(PVA with 0.0005 wt.% MXene and 4.7 wt.% TEDA.C) highest discharged energy density(17.32 J/cm3)which is 1.53 times of that of 1788PVA.