High-entropy enhanced capacitive energy storage

Electrostatic dielectric capacitors are essential components in advanced electronic and electrical power systems due to their ultrafast charging/discharging speed and high power density. A major challenge, however, is how to improve their energy densities to effectuate the next-generation applications that demand miniaturization and integration. Here, we report a high-entropy stabilized Bi2Ti2O7-based dielectric film that exhibits an energy density as high as 182 J cm−3 with an efficiency of 78% at an electric field of 6.35 MV cm−1. Our results reveal that regulating the atomic configurational entropy introduces favourable and stable microstructural features, including lattice distorted nano-crystalline grains and a disordered amorphous-like phase, which enhances the breakdown strength and reduces the polarization switching hysteresis, thus synergistically contributing to the energy storage performance. This high-entropy approach is expected to be widely applicable for the development of high-performance dielectrics. Electrostatic capacitors can enable ultrafast energy storage and release, but advances in energy density and efficiency need to be made. Here, by doping equimolar Zr, Hf and Sn into Bi4Ti3O12 thin films, a high-entropy stabilized Bi2Ti2O7 pyrochlore phase forms with an energy density of 182 J cm−3 and 78% efficiency.