Boosting energy storage properties of BNT-based relaxor ferroelectric ceramics via (Zn_1/3Nb_2/3)⁴⁺ complex ion doping

High power density electrostatic capacitor is a fundamental component of advanced electrical and electronic systems. Herein, the (Zn_1/3Nb_2/3)⁴⁺ complex ion was introduced into the B-site of Bi_0.385Na_0.325Ba_0.105Sr_0.155TiO₃ relaxor ferroelectric ceramics to improve energy storage properties and dielectric temperature stability. All pseudo-cubic structured ceramics have clear grain boundaries with an average grain size of 1 ~ 2 μm. In the optimized composition, a recoverable energy density of 2.4 J/cm³ with an energy efficiency of 78% can be achieved under a relatively low electric field of 160 kV/cm, together with excellent stability and reliability of energy storage in temperature, frequency, and cycling fields, as well as fast charging–discharging rate. This work provides guidance for the design of high-performance energy storage dielectric materials by enhancing the B-site disorder of relaxor ferroelectric ceramics via complex ion doping.