铌镥酸铅基反铁电单晶的相界调控、储能特性及相变机理研究

Antiferroelectric (AFE) material possesses excellent electrical properties, such as high energy density, fast discharge time, good fatigue resistance and abundant structural phase transitions under the external electric field, temperature or stress. Therefore, AFE has become a research hotspot in new energy sources and devices. Lead lutetium niobate (PLN) possess high energy storage characteristic with ultrahigh phase transition electric field and it is easy to crack due to large strain which is caused by phase transition. In order to solve the problems of high electric field and poor quality of PLN system, new types of large-size, high-quality AFE crystals with low critical field and excellent electrical properties are expected to obtain by means of phase boundary control. Therefore, this project focuses on three key scientific issues of PLN-based AFE crystals: “phase boundary regulation”, “doping mechanism of A/B sites” and “AFE/FE phase transition theory”. The phase transition electric field, temperature and response time can be effectively controlled by controlling the composition, external electric field, temperature and crystallographic orientation, making PLN-based single crystal endowed with the tunable energy storage and charge-discharge characteristics. This project aims to understand the phase boundary regulation through A/B sites ions doping and multicomponent composite, and discuss the relationships between phase structure, crystallographic orientation, microstructure and excellent electrical properties, such as high energy storage, fast discharge, etc.

反铁电材料具备能量密度高、放电时间快、抗疲劳性好等优异电学特性，且在电场、温度或应力作用下可以发生丰富的结构相变，因此成为研究新型能源与器件的热点材料。铌镥酸铅（PLN）具有优异的能量储存特性，但其相变临界电场高，材料极易因相变产生的大应变而开裂。针对PLN基反铁电晶体相变电场高、单晶质量差等问题，通过相界调控手段有望获得相变临界场较低、电学性能优异的新型反铁电单晶。因此，本项目针对PLN基反铁电单晶“相界调控规律”、“A/B位掺杂机制”、“反铁电/铁电相变行为解释”三个关键科学问题开展研究，通过控制晶体组分、外加电场、温度及结晶学取向，调控相变电场、相变温度和相变响应时间，研究PLN基单晶可调变的储能密度、充放电时间等电学特性。旨在掌握A/B位离子掺杂、多元复合对PLN晶体的相界调控规律，深入探讨晶体相结构、结晶学取向及其微观结构特征与高储能、快放电等优异电学性能的关联关系。

反铁电材料（AFE）具备能量存储密度高、充放电时间快、抗疲劳性好等电学特性，且在电场、温度或应力作用下可以发生丰富的结构相变，因此成为研究新型能源与器件的热点材料。铌镥酸铅（PLN）具有优异的能量储存特性，但其相变临界电场高，材料极易因相变产生的大应变而开裂。本项目针对PLN基反铁电材料存在的问题，通过相界调控手段获得相变临界场适中、电学性能优异的新型反铁电材料。因此，本项目主要研究内容是通过控制材料组分、外加电场、温度及结晶学取向，调控相变电场、相变温度和相变响应时间，研究PLN基反铁电材料可调变的储能密度、充放电时间等电学特性，掌握A/B位离子掺杂、复合对PLN体系的相界调控规律，深入探讨反铁电材料相结构、结晶学取向及其微观结构特征与高储能、快放电等优异电学性能的关联关系。