Boosting High Electric Breakdown Strength for Excellent Energy Storage Performance in Bi0.5Na0.5TiO3-Based Lead-Free Ceramics via a High Entropy Strategy

Pu Mao; Yongguang Guo; Ting Wang; Liqiang He; Wanjin Li; Zhiyong Liu; Bing Xie; Kun Guo; Longlong Shu; Jinghui Gao

doi:10.1021/acsami.4c15339

Boosting High Electric Breakdown Strength for Excellent Energy Storage Performance in Bi_0.5Na_0.5TiO₃-Based Lead-Free Ceramics via a High Entropy Strategy

ACS Appl Mater Interfaces. 2025 Jan 8;17(1):1485-1498. doi: 10.1021/acsami.4c15339. Epub 2024 Dec 17.

Authors

Pu Mao^{1

2}, Yongguang Guo¹, Ting Wang³, Liqiang He⁴, Wanjin Li¹, Zhiyong Liu¹, Bing Xie¹, Kun Guo¹, Longlong Shu⁵, Jinghui Gao²

Affiliations

¹ Jiangxi Key Laboratory of Extreme Manufacturing Technology for High-end Equipment, School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China.
² State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an, Shannxi 710049, China.
³ Guangdong Provincial Key Laboratory of Electronic Functional Materials and Devices, Huizhou University, Huizhou, Guangdong 516001, China.
⁴ Frontier Institute of Science and Technology, and State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
⁵ School of Physics and Materials Science, Nanchang University, Nanchang 330031, China.

PMID: 39686873
DOI: 10.1021/acsami.4c15339

Abstract

High-performance dielectric capacitors featuring large recoverable energy storage density (W_rec) and high discharge efficiency (η) are beneficial to realize the device miniaturization, lightweight property, and sustainability of advanced pulse power systems. The obtainment of a high electric breakdown strength (E_b) is crucial for improving the energy storage performance of dielectric materials. However, as for Bi_0.5Na_0.5TiO₃ (BNT) lead-free relaxor ferroelectric ceramics, the relatively lower E_b directly limits their electrical performance improvement and practical applications. Herein, a popular high entropy strategy was employed to rationally design and prepare the (Bi_0.5Na_0.5)_x(Sr_0.25Ba_0.25La_0.25K_0.25)_(1-x)TiO₃ (BNSLBKT-x) lead-free relaxor ferroelectric ceramics based on the BNT matrix. Encouragingly, the BNSLBKT-0.2 high-entropy ceramic exhibits a high E_b of 510 kV/cm, and this can be ascribed to the refined grains and enhanced activation energy. Moreover, it is confirmed that the polar nanoregions (PNRs) exist in the BNSLBKT-0.2 ceramic by the piezoresponse force microscopy (PFM) and transmission electron microscopy (TEM) characteristics, further strengthening relaxation behaviors and decreasing remanent polarization (P_r). It is anticipated that a high W_rec of 4.6 J/cm³ and a good η of 86% are obtained in this BNSLBKT-0.2 high-entropy ceramic. More importantly, the BNSLBKT-0.2 ceramic displays excellent frequency stability of capacitive energy storage at 10-1000 Hz and good temperature stability at 20-140 °C. The fast discharge rate (τ_0.9 = 0.26 μs) and the high P_D of 49.2 MW/cm are also achieved in this BNSLBKT-0.2 ceramic. The findings demonstrate that this high entropy design is an effective strategy for developing dielectrics with excellent energy storage capability to meet the requirements of modern dielectric capacitor applications.

Keywords: BNT-based lead-free ceramics; energy storage performances; high electric breakdown strength; high entropy; polar nano region.