电场诱导反铁电相和铁电相发生相互转变(反铁电-铁电相变)使得反铁电陶瓷成为高性能脉冲电容器的重要候选材料。然而，反铁电-铁电相变在带来较高储能密度的同时还伴随着较大的体积应变，导致反铁电陶瓷在电场循环加载作用下发生开裂失效。针对这一问题，申请人从反铁电陶瓷的微观结构出发，通过前期工作揭示了位错是PbZrO3基反铁电陶瓷的共性微观结构特征，并且位错与反铁电-铁电相变存在强烈的耦合作用。在此基础上，本项目拟以高储能密度的PLZST反铁电陶瓷为主要研究对象，分析反铁电陶瓷中位错的形成机制和位错运动的临界应力条件，阐明位错和反铁电-铁电相变的耦合作用，揭示位错对开裂失效的影响规律，进而通过位错调控抑制裂纹的萌生和扩展，以期在保证反铁电陶瓷高储能密度的同时延长其循环寿命。本项目的成功实施对于反铁电陶瓷的综合性能优化和实际工程应用具有重要意义。

Benefitting from electric field induced phase transition between antiferroelectric (AFE) state and ferroelectric (FE) state (AFE-FE phase transition), AFE ceramics have become one of the most promising candidates for high-performance pulse capacitor. However, the AFE-FE phase transition always generates large strain, which will cause fracture failure after several hundreds or thousands of charging/discharging cycles. To solve this problem, we had studied the microstructure of PbZrO3-based AFE ceramics in details. Our results reveal that the PbZrO3-based AFE ceramics have high density of dislocation, which can strongly coupling with the AFE-FE phase transition. Focusing on the PLZST AFE ceramics with relatively high energy-storage density, this project will firstly study the physical origins of dislocation and kinetics of dislocation motion and then reveal the law of coupling effects between dislocation and AFE-FE phase transition. After then, we will try to obtain in-depth understanding on the mechanism of fracture failure during charging/discharging cycles. Finally, the optimization of cycle lifetime will be explored by tuning the parameters of dislocation to inhibit the initiation and propagation of cracks. The achievements of this project will provide important principle and mechanism for optimization of comprehensive performance of PbZrO3-based AFE ceramics in pulsed power application.