Boosting energy storage performance of relaxor Na0.5Bi0.5(Fe0.03Ti0.97)O3/Na0.5Bi0.5(Zr0.02Ti0.98)O3-based multilayer thin films under moderate electric field via aging & treating processing

Na 0.5 Bi 0.5 (Fe 0.03 Ti 0.97 )O 3 /Na 0.5 Bi 0.5 (Zr 0.02 Ti 0.98 )O 3 (NBFT/NBZT)-based relaxor multilayer thin films are successfully prepared on Pt/Ti/SiO 2 /Si substrate via a sol-gel method. Abundant interfaces are brought in by periodically stacking the building block of one single unit between NBFT & NBZT to form various structures and consequentlly, high dependence of energy storage performance on the number of interface is noted. Considering the structural relaxation of the multilayers, aging and treating are taken from the prospective of improving energy storage performance at a relatively stable state. Accordingly, after aging for 21 d and treating, a relatively large recoverable energy storage density ( W rec ) and an efficiency ( η ) of 71.7 J/cm 3 and 74.1% are obtained, respectively at room temperature. Excellent thermal stability for W rec and η are also noticed with the rates of change of ≤6.5% and ≤5%, respectively for W rec and η from 225 to 498 K, along with the corresponding values of ≤2.0% and ≤4.2% after fatigue endurance of 10 7 cycles. These findings provide an effective way of designing NBT-based multilayer thin film for energy storage devices. ● NBFT/NBZT-based relaxor thin films with abundant interfaces are prepared. ● Aging and treating are taken to obtain a relatively stable state. ● Residual stress releasing and dipoles stablization contribute to the performance. ● Large W rec of 71.7 J/cm 3 and η of 74.1% are achieved for (NBFT/NBZT) 5 /NBFT. ● High thermal stability, frequency stability and fatigue endurance are obtained.