Superior energy storage in Sn-doped BaTiO3 thin-film capacitors with a slush-like polar state
Zouhair Hanani, Soukaina Merselmiz, Blaž Jaklič, Petruša Borštnar, Nina Daneu, A. G. Razumnaya, Yuri Tikhonov, V. Bobnar, Igor Lukyanchuk, Matjaž Spreitzer
Abstract
Relaxor ferroelectrics are highly valued in energy storage for their high recoverable energy density and efficiency. To address environmental concerns over lead-based materials, this study explores Sn-doped BaTiO 3 (BaTi 0.89 Sn 0.11 O 3 , BTSn) thin films as a lead-free alternative. BTSn films, grown via pulsed laser deposition on a SrTiO 3 substrate with a LaNiO 3 electrode, achieve 105 J cm −3 energy density and 80 % efficiency at 8.5 MV cm −1 , with a figure-of-merit of 1125 J cm −3 at 6 MV cm −1 . They also demonstrate excellent thermal stability (0–140 °C) and durability through 10 10 charge–discharge cycles. The high breakdown strength was attributed to the absence of Ti 3+ and the presence of nanodomains (1–3 nm) with slush-like polar structures. A correlation between the local Sn content and B-site displacement indicates that polar nanodomains, measuring 2–4 unit cells in size, exhibit large displacements and are Sn-deficient. These findings suggest that BTSn thin films offer a promising, reliable, and eco-friendly alternative for next-generation energy storage systems, contributing to global sustainability efforts by reducing reliance on hazardous lead-based materials.