Large recoverable energy storage density and low sintering temperature in potassium‐sodium niobate‐based ceramics for multilayer pulsed power capacitors

Multilayer pulsed power ceramic capacitors require that dielectric ceramics possess not only large recoverable energy storage density (W_rec) but also low sintering temperature (<950°C) for using the inexpensive metals as the electrodes. However, lead‐free bulk ceramics usually show low W_rec (<2 J/cm³) and high sintering temperature (>1150°C), limiting their applications in multilayer pulsed power ceramic capacitors. In this work, large W_rec (~4.02 J/cm³ at 400 kV/cm) and low sintering temperature (940°C) are simultaneously achieved in 0.9(K_0.5Na_0.5)NbO₃–0.1Bi(Mg_2/3Nb_1/3)O₃–1.0 mol% CuO ceramics prepared using transition liquid phase sintering. W_rec of 4.02 J/cm³ is 2‐3 times as large as the reported value of other (Bi_0.5Na_0.5)TiO₃ and BaTiO₃‐based lead‐free bulk ceramics. The results reveal that 0.9(K_0.5Na_0.5)NbO₃–0.1Bi(Mg_2/3Nb_1/3)O₃–1.0 mol% CuO ceramics are promising candidates for fabricating multilayer pulsed power ceramic capacitors.