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/cm 3 ) and high sintering temperature (>1150°C), limiting their applications in multilayer pulsed power ceramic capacitors. In this work, large W rec (~4.02 J/cm 3 at 400 kV/cm) and low sintering temperature (940°C) are simultaneously achieved in 0.9(K 0.5 Na 0.5 )NbO 3 –0.1Bi(Mg 2/3 Nb 1/3 )O 3 –1.0 mol% CuO ceramics prepared using transition liquid phase sintering. W rec of 4.02 J/cm 3 is 2‐3 times as large as the reported value of other (Bi 0.5 Na 0.5 )TiO 3 and BaTiO 3 ‐based lead‐free bulk ceramics. The results reveal that 0.9(K 0.5 Na 0.5 )NbO 3 –0.1Bi(Mg 2/3 Nb 1/3 )O 3 –1.0 mol% CuO ceramics are promising candidates for fabricating multilayer pulsed power ceramic capacitors.