Simultaneously enhanced energy storage performance and luminance resistance in (K_0.5Na_0.5)NbO₃-based ceramics via synergistic optimization strategy

The rapidly advancing energy storage performance of dielectric ceramics capacitors has garnered significant interest for applications in fast charge/discharge and high-power electronic techniques. Exploring the exceptional electrical properties in harsh environments can further promote their practical applications. Defect carriers can be excited under luminance irradiation, thereby leading to degradation of energy storage performance. Herein, a synergic optimization strategy is proposed to enhance energy storage properties and luminance resistance of (K_0.5Na_0.5)NbO₃-base (KNN) ceramics. First, the introduction of Bi(Zn_0.5Ti_0.5)O₃ solid solution and La³⁺ ions disrupts the long-range polar orders and enhances super paraelectric relaxation characteristics. Additionally, doping La³⁺ ions can increase the band gap and reduce oxygen vacancy concentration, resulting in excellent luminance resistance. Finally, the viscous polymer process is employed to suppress the grain growth and promote chemical homogeneity. As a result, ultrahigh recoverable energy storage density (W_rec) of 8.11 J/cm³ and high efficiency (η) of 80.98% are achieved under an electric field of 568 kV/cm. Moreover, the variations in W_rec and η are only 12.45% and 1.75%, respectively, under 500 W xenon lamp irradiation compared to the performance under a dark environment. These findings hold great potential in facilitating the practical application of dielectric ceramic capacitors in luminance irradiation environments.