Enhanced energy storage density of Bi_3.25La_0.75Ti₃O₁₂ thin films by preferred orientation and interface engineering

Dielectric energy storage capacitors are promising avenues for high power density and fast charge/discharge applications. This study focused on the deposition of Bi_3.25La_0.75Ti₃O₁₂ (BLT) films onto Pt/Ti/SiO₂/Si substrates by a sol-gel technology. Through the synergistic strategy of interface engineering and the preferred orientation of BLT film, the residual polarization was minimized, and the breakdown field strength was enhanced. As a result, the recoverable energy density (U_rec) was significantly improved to 62.97 J/cm³ with a high energy storage efficiency (η) of 85.88 %. Notably, the synthesized BLT film exhibited excellent temperature (25–150 °C) and frequency (100 Hz-10 kHz) stability of U_rec (>30 J/cm³) and η (>75 %) at ∼2200 kV/cm. The finding demonstrates the potential of BLT thin film as a lead-free material for the next generation of pulse power capacitors. Overall, the synergistic approach of interface engineering and preferred orientation proves to be an effective way to improve the performance of dielectric energy storage capacitors.