Dielectric property optimization of polymer nanocomposites using BaTiO3 based high-entropy ceramic filler with Dirac-cone effect

BaTiO3 (BTO) based nanoceramics play an important role in electronic devices. Here, we synthesized three BTO-based high-entropy nanoceramics and calculated their band gaps via density functional theory (DFT). Firstly, cubic high-entropy ceramic powders, namely (La0.2Ca0.2Sr0.2Ba0.2Li0.2)TiO3, Ba(Ti0.2Sn0.2Zr0.2Hf0.2Nb0.2)O3 and Ba(Ti0.2Sn0.2Hf0.2Zr0.2Ta0.2)O3, were synthesized. Then, composition and morphology of powders was determined. Ultimately, their band gaps were calculated. We clarified the influence of metal co-doping on band gaps. Dirac-cone band-structure was found in Ba(Ti0.2Sn0.2Zr0.2Hf0.2Nb0.2)O3. Compared with BTO (band gap 1.821 eV), BTO-based high-entropy ceramics can have the reduced band gaps (1.549 eV; 0.001 eV; 0 eV) using various co-doping. By high-entropy strategy, conductive ability of BTO-based ceramic is regulated. Experimental results of polymer/ceramic composite dielectrics and theoretical results of ceramics are consistent. Dirac-cone ceramic filler is promising for preparing polymer-based composites for energy storage. This research enables mass preparation of high-entropy ceramic/polymer dielectric composites.