Enhancing the Energy Storage Properties and Breakdown Strength of Lead-Free Bismuth-Sodium Titanate-Based Ceramics Through NaNbO<sub>3</sub> Doping

Dielectric capacitors with a high density of recoverable energy storage are extremely desirable for a variety of uses. However, these capacitors often exhibit lower breakdown strengths and energy efficiency compared to other materials, which poses significant challenges for their practical use. We r...

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Main Authors: Jingxia Gao, Haizhou Guo, Hongxia Li, Hui Li, Liqin Yue, Rui Wang, Jiangyan Si, Qiaoqiao Zhao, Yangyang Zhang
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Crystals
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Online Access:https://www.mdpi.com/2073-4352/15/3/287
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Summary:Dielectric capacitors with a high density of recoverable energy storage are extremely desirable for a variety of uses. However, these capacitors often exhibit lower breakdown strengths and energy efficiency compared to other materials, which poses significant challenges for their practical use. We report on a novel antiferroelectric ceramic system in the present study, (1 − <i>x</i>){0.97[0.985(0.93Bi<sub>0.5</sub>Na<sub>0.5</sub>TiO<sub>3</sub>–0.07BaTiO<sub>3</sub>)–0.015Er)]–0.03AlN}–<i>x</i>NaNbO<sub>3</sub> (<i>x</i> = 0, 10 wt%, 20 wt%, 30 wt%, and 40 wt%), synthesized via a conventional solid-state reaction approach. Here, (Bi<sub>0.5</sub>Na<sub>0.5</sub>TiO<sub>3</sub>–BaTiO<sub>3</sub>) is denoted as BNT–BT. We observed that varying the NaNbO<sub>3</sub> (NN) content gradually refined the grain size of the ceramics, narrowed their hysteresis loops, and transformed their phase structure from antiferroelectric to relaxor ferroelectric. These changes enhanced breakdown strength (<i>E</i><sub>b</sub>), thus increasing the performance of energy storage. Specifically, the recoverable energy density (<i>W</i><sub>rec</sub>) and energy storage efficiency <i>(η</i>), respectively, reached 0.67–1.06 J/cm<sup>3</sup> and 44–88% at electric fields of 110–155 kV/cm, with the highest performance observed at 30 wt% NN doping. Additionally, over a broad range of temperature and frequency, the 70 wt% {0.97[0.985(BNT–BT)–0.015Er]–0.03AlN}–30 wt% NN ceramic demonstrated exceptional stability in energy storage. These results demonstrate the significant potential of lead-free(1 − <i>x</i>)({0.97[0.985(BNT–BT)–0.015Er]–0.03AlN}–<i>x</i>NN ceramics for the applications of high-performance energy storage.
ISSN:2073-4352