High-performance Dy2Ti2O7 pyrochlore ceramics for dielectric energy storage: sintering temperature studies

Abstract

Pyrochlore-type Dy₂Ti₂O₇ (DTO) ceramics were fabricated via a solid-state reaction method. The influence of sintering temperature on their microstructure and energy storage performance (ESP) was systematically investigated. The optimal sintering temperature was identified as 1500 °C, under which the DTO ceramic exhibited a dense and uniform microstructure, a wide bandgap, low oxygen vacancy concentration and weak interfacial polarization. These characteristics synergistically enhanced both the breakdown strength (E_b) and polarization difference (ΔP), leading to an excellent recoverable energy density (W_rec) of 4.63 J cm⁻³ and a high energy-storage efficiency (η) of 92.44%. Additionally, the optimized ceramic demonstrated outstanding stability, with a relative variation of efficiency Δη/η ≤ 3.1% over 20–140 °C and a relative variation of recoverable energy density ΔW_rec/W_rec ≤ 2.6% over 10–200 Hz at room temperature. This work demonstrates that pyrochlore-type ceramics are promising candidates for high-performance lead-free energy-storage applications, and sintering engineering can effectively optimize their energy-storage properties.