Phase Modulation Leads to Ultrahigh Energy Storage Performance in AgNbO₃-Based Ceramics and Multilayer Capacitors

Antiferroelectric (AFE) ceramics are competitive energy storage candidates for advanced high-power devices. However, the poor recoverable energy density and efficiency are challenging and severely hinder their applications. Here, superior energy storage performance is obtained in Bi³⁺-, Sr²⁺-, and Ta⁵⁺-codoped AgNbO₃-based ceramics. Specifically, with the effective phase modulation via Bi³⁺, the paraelectric T phase stabilizes at room temperature and facilitates a recoverable energy storage density of 9.27 J/cm³ and an efficiency of 83.2% in (Ag_0.71Bi_0.07Sr_0.04)(Nb_0.85Ta_0.15)O₃ ceramics. The corresponding multilayer ceramic capacitor (MLCC) further promotes the recoverable energy storage density to 14.32 J/cm³ and efficiency to 97.8%, which is almost the best comprehensive energy storage performance among AN-based ceramics and MLCCs to the best of our knowledge. The proposed strategy is generally applicable to design high-performance energy storage devices and other functionalities of AFE dielectric materials.