北京科技大学陈骏团队报道了无Pb巨大电容储能弛豫剂的化学设计。相关研究成果发表在2023年5月19日出版的《美国化学会杂志》。

介电电容器在先进的电气和电子系统中引起了极大的关注。由于成分多样性高和缺乏通用指南，开发具有高能量密度和高存储效率的电介质具有挑战性。

该文中，研究人员提出了一个包含钙钛矿结构畸变（δ）和容限因子（t）的映射图，以设计具有极高电容储能的无Pb弛豫剂。该图谱显示了如何选择具有大δ和顺电成分的铁电体来形成t值接近1的弛豫剂，从而在高击穿下获得消除的磁滞和大极化。以Bi_0.5Na_0.5TiO₃基固溶体为例，研究人员证明了成分驱动的局部原子极性位移的主要有序-无序特性赋予了弛豫剂在几个纳米尺度上，具有类似雪泥的结构和强烈的局部极性波动。这导致了13.6 J cm^–3的巨大可回收能量密度，以及94%的超高效率，这远远超出了无铅大块陶瓷中报道的当前性能边界。

该工作通过合理的化学设计为获得具有优异储能性能的无铅弛豫剂提供了解决方案。

附：英文原文

Title: Chemical Design of Pb-Free Relaxors for Giant Capacitive Energy Storage

Author: Hui Liu, Zheng Sun, Ji Zhang, Huajie Luo, Qinghua Zhang, Yonghao Yao, Shiqing Deng, He Qi, Jue Liu, Leighanne C. Gallington, Joerg C. Neuefeind, Jun Chen

Issue&Volume: May 19, 2023

Abstract: Dielectric capacitors have captured substantial attention for advanced electrical and electronic systems. Developing dielectrics with high energy density and high storage efficiency is challenging owing to the high compositional diversity and the lack of general guidelines. Herein, we propose a map that captures the structural distortion (δ) and tolerance factor (t) of perovskites to design Pb-free relaxors with extremely high capacitive energy storage. Our map shows how to select ferroelectric with large δ and paraelectric components to form relaxors with a t value close to 1 and thus obtaining eliminated hysteresis and large polarization under a high electric breakdown. Taking the Bi0.5Na0.5TiO3-based solid solution as an example, we demonstrate that composition-driven predominant order–disorder characteristic of local atomic polar displacements endows the relaxor with a slushlike structure and strong local polar fluctuations at several nanoscale. This leads to a giant recoverable energy density of 13.6 J cm–3, along with an ultrahigh efficiency of 94%, which is far beyond the current performance boundary reported in Pb-free bulk ceramics. Our work provides a solution through rational chemical design for obtaining Pb-free relaxors with outstanding energy-storage properties.

DOI: 10.1021/jacs.3c02811

Source: https://pubs.acs.org/doi/10.1021/jacs.3c02811