Achieving Ultrahigh Energy Storage Density for BaTiO₃-Based Ceramics under Moderate Electric Fields via Regulating...

The development of lead-free relaxor ferroelectric ceramics with high energy storage density has emerged as a critical area, driven by the increasing demand for advanced energy storage capacitors and high-power density devices. Conventional approaches to enhance energy-storage performance in lead-free dielectric ceramics typically rely on achieving ultrahigh breakdown field strength (E_b) or employing complex multicomponent composite strategies. However, the requirement for high electric fields hinders the miniaturization and integration of the devices. Furthermore, despite extensive research on the classic BaTiO₃-based system, recoverable energy storage densities exceeding 6 J/cm³ remain exceedingly rare, especially under moderate electric fields (300 kV/cm < E < 500 kV/cm). In this paper, based on the relationship of energy storage among dielectric permittivity (ε_r) and electric field ($$), we constructed a superparaelectric state near room temperature and improved ε_r by introducing centrosymmetric BiScO₃ into a high ε_r matrix (Ba_0.65Sr_0.3Ca_0.05Sn_0.02Ti_0.08O₃). Ultimately, this strategy enables the realization of an ultrahigh energy storage density of 6.95 J/cm³ and a high energy efficiency of 86.17% under moderate electric fields (500 kV/cm). These findings provide a practical and innovative pathway for developing high-performance energy storage capacitors, advancing the potential for lead-free dielectric ceramics in next-generation energy storage technologies.