Fatigue resistant lead-free multilayer ceramic capacitors with ultrahigh energy density

The critical role of electrical homogeneity in optimising electric-field breakdown strength (BDS) and energy storage performance in high energy density lead-free capacitors is demonstrated, resulting in exceptional BDS for bulk ceramics and multilayers with values of ~260 and ~950 kV cm-1, respectively. The high BDS gives rise to the record-performance recoverable energy density (Wrec) of 13.8 J cm-3 with an efficiency (η) of 81% in multilayers up to now among all lead/lead-free dielectric materials. The multilayers are temperature stable up to 100 °C, stable with respect to frequency in the range 10-2 to 102 Hz, low strain and fatigue-resistant up to 104 cycles (Wrec variation < 10%). These properties show promise for practical use in pulsed power systems.