Ultrahigh-Efficiency Superior Energy Storage in Lead-Free Films with a Simple Composition
Tianyu Li, Shiqing Deng, Ruixue Zhu, Jiyuan Yang, Shiqi Xu, Yongqi Dong, Hui Liu, Chuanrui Huo, Peng Gao, Zhenlin Luo, Oswaldo Diéguez, Houbing Huang, Shi Liu, Long‐Qing Chen, He Qi, Jun Chen
Abstract
Dielectric capacitors are highly desired in modern electronic devices and power systems to store and recycle electric energy. However, achieving simultaneous high energy density and efficiency remains a challenge. Here, guided by theoretical and phase-field simulations, we are able to achieve a superior comprehensive property of ultrahigh efficiency of 90–94% and high energy density of 85–90 J cm –3 remarkably in strontium titanate (SrTiO 3 ), a linear dielectric of a simple chemical composition, by manipulating local symmetry breaking through introducing Ti/O defects. Atomic-scale characterizations confirm that these Ti/O defects lead to local symmetry breaking and local lattice strains, thus leading to the formation of the isolated ultrafine polar nanoclusters with varying sizes from 2 to 8 nm. These nanoclusters account for both considerable dielectric polarization and negligible polarization hysteresis. The present study opens a new realm of designing high-performance dielectric capacitors utilizing a large family of readily available linear dielectrics with very simple chemistry.