Sintering aids engineering for high-performance energy storage in tungsten bronze ceramics

Abstract

Dielectric ceramics are critical for pulsed power applications owing to their high-power density and rapid charge-discharge capabilities. Among them, tetragonal tungsten bronze (TTB)-type ceramics have attracted attention as potential energy-storage materials due to their non-volatile compositions and structural adaptability. However, previous studies have primarily focused on regulating energy storage performance through multi-element doping, with relatively little attention paid to optimizing the sintering process to enhance the inherent performance of ceramics. In this work, we demonstrate an alternative and effective strategy to improve the intrinsic energy-storage performance in TTB-structured Sr_0.6Ba_0.4Nb₂O₆ (SBN) ceramics through the incorporation of sintering aids, including MnO₂, CuO, and Li₂CO₃, rather than complex compositional doping. The influence of these additives on the microstructure, dielectric behavior, and energy-storage characteristics is systematically investigated. Results show that CuO-modified SBN ceramics achieve a high recoverable energy density of 4.41 J/cm³, representing a 128% enhancement compared to pristine SBN ceramic, along with an efficiency of 93.4%. This superior performance is attributed to the synergistic effects of enhanced densification and strengthened relaxor characteristics. Moreover, the ceramic presents excellent thermal (25-125 °C) and frequency stability (1-200 Hz). Our findings highlight sintering-aid engineering as a facile route to significantly enhance the energy-storage performance of SBN ceramics, thereby laying a foundation for the performance optimization of TTB-structured energy-storage ceramics.

Keywords

Dielectric capacitor / ferroelectrics / energy storage / tungsten bronze / relaxor ferroelectric

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