Excellent energy storage density of Bi3.25La0.75Ti3O12/Bi0.5Na0.5TiO3 multilayer thin films

Dielectric energy storage capacitors have gained much attention for high power density and fast charge/discharge rate. In this study, a novel laminated structure design was prepared using Bi
3.25
La
0.75
Ti
3
O
12
(BLT) /Bi
0.5
Na
0.5
TiO
3
(BNT) multilayer dielectric thin film materials, which deposited on Pt/Ti/SiO
2
/Si substrates by using a sol-gel technology. Dielectric properties, energy storage properties, and oxygen vacancy concentration of BLT/BNT multilayer thin film were investigated. All multilayer thin films have a high-density microstructure and good energy storage performance, B7 multilayer thin film achieving the highest breakdown strength (~3984.19 kV/cm), recoverable energy storage density (U
rec
) of 81.73 J/cm
³
, and energy storage efficiency (η) of 82.74%. Additionally, B7 multilayer thin film exhibited excellent temperature and frequency stability, with U
rec
varying by less than 3% in a wide temperature range (25-175 ℃), and less than 5% within the range of 200 Hz-10 kHz. The results demonstrate that the (BLT/BNT) multilayer thin film is a promising energy storage material with good prospects. The design for the fabrication of a high energy storage density, good stability, and lead-free medium energy storage material provides a new train of thought.