Correlation between leakage conductance and interface charge density in PVC-based composite dielectrics filled with various carbon-based conductive particles

Carbon-based conductive particle/polymer composites exhibit high leakage conductance. Therefore, this study focuses on evaluating the density and injection depth of interface charges in polyvinyl chloride (PVC)-based composites containing titanium carbide (Ti2C) MXene, needle coke, hafnium carbide (HfC), and single-walled carbon nanotubes (SWCNTs). Four types of PVC/filler particle composites were prepared, and their dielectric, conductivity, and breakdown properties were measured. Among these, PVC/Ti2C MXene composite with 12 wt% filler exhibited the most balanced electric characteristics, such as a dielectric constant of similar to 224 and loss of similar to 0.76 at 100 Hz, accompanied by a breakdown strength of similar to 10(5) MV m(-1). Interface charge densities and injection depths of composites were determined using experimental data and a theoretical model. For the PVC/Ti2C MXene composite with 9 wt% filler, interface charge density and injection depth at 100 Hz theoretically were (7.2 +/- 2.6) x 10(-5) C m(-2) and (0.10 +/- 0.03) mu m, respectively. The relationship between high leakage conductance and interface charge density was explained, highlighting that a high interface charge density enables the release of numerous leakage conductance charges into PVC. This study contributes to the fabrication of promising composites for energy storage by controlling the interface charge density and injection depth.