Fatigue-free dielectric capacitor with giant energy density based on lead-free Na_(0.5)Bi_(0.5)TiO_3-based film

摘要

Lead-free inorganic dielectric film capacitors have ignited plenty of interest in developing the dielectric energy storage. Here, we obtained a 0.5 mol% Ce and 2 mol% Mn-codoped 0.94Na_(0.5)Bi_(0.5)TiO_3-0.06BaTiO_3 [(Ce,Mn):NBT-BT] ceramic film capacitor on Pt/TiO_2/SiO_2/Si substrate, which has a significantly improved recoverable energy storage density W_(rec) ~ 64.2 J/ cm3 and efficiency η -68.1% at 2105 kV/cm. The film capacitor exhibits superior frequency stability with small gradient of 5.9% for W_(rec) in the frequency range of 500 Hz to 20 kHz, and excellent cycling reliability over 10~8 charge-discharge cycles without fatigue deterioration. Besides, the (Ce,Mn):NBT-BT film capacitor has large discharged energy density of 43.0 J/ cm~3 at 1579 kV/cm and fast discharging speed of 55.1 μs tested by a resistance—capacitance circuit with a load resistor of 100 kΩ. These findings indicate that the (Ce,Mn):NBT-BT film might be promising lead-free dielectrics for energy storage applications.