High-temperature BaTiO₃-based ceramic capacitors by entropy engineering design

High-performance BaTiO₃(BTO)-based dielectric ceramics have great potential for high-power energy storage devices. However, its poor temperature reliability and stability due to its low Curie temperature impedes the development of most electronic applications. Herein, a series of BTO-based ceramics are designed and prepared on the basis of entropy engineering. Owing to the incorporation of Bi(Mg_0.5Ti_0.5)O₃, relaxation behavior and low dielectric loss at high temperatures have been achieved. Moreover, the high-entropy strategy also promotes lattice distortion, grain refinement and excellent resistance, which together increase the breakdown field strength. These simultaneous effects result in outstanding energy storage performance, ultimately achieving stable energy density (U_e) of 5.76 J·cm⁻³ and efficiency ( $\eta$) of 89%. Most importantly, the outstanding temperature stability makes high-entropy BTO-based ceramics realize a significant energy storage density of 4.90 $\pm$0.14 J·cm⁻³ with the efficiency above 89%, spanning a wide temperature range of 25–250 °C, as well as cycling reliability with negligible performance deterioration after 3 $\times$10⁵ cycles at 300 kV∙cm⁻¹ and 200 °C. This research presents an effective method for designing temperature-stable and reliable dielectrics with comprehensive energy storage performance.