# Wet Chemical-Synthesized Low-Loss Dielectric Composite Material Based on CuCl-Cu7S4 Nanoparticles and PVDF Copolymer

## TL;DR

A new composite material with high energy storage potential is created using copper sulfide nanoparticles and a PVDF copolymer.

## Contribution

A low-loss dielectric composite with enhanced permittivity using Cu7S4 nanoparticles in PVDF is developed.

## Key findings

- Adding 6% Cu7S4 nanoparticles increases dielectric permittivity from 10.4 to 15.9 at 1 kHz.
- The composite maintains a low dielectric loss coefficient of less than 0.1.
- Nanoparticles alter the composite's surface morphology and crystalline phases.

## Abstract

Polymer composites with high dielectric permittivity (>10) and low dielectric loss are critical for energy storage and microelectronic applications. This study reports on a semi-transparent composite of a PVDF copolymer filled with Cu7S4 nanoparticles synthesized via a wet chemical route. Only a small content (6%) of copper sulfide increases the dielectric permittivity of the material from 10.4 to 15.9 (1 kHz), maintaining a low dielectric loss coefficient (less than 0.1). The incorporated nanoparticles affect the morphology of the composite film surface and crystalline phases in the whole volume, which was studied with FTIR spectroscopy, differential scanning calorimetry and scanning probe microscopy.