La3 + modified BaBi4Ti4O15 bismuth layer-structured ceramics toward high energy storage density and efficiency

Abstract

Owing to alternate (Bi₂O₂)²⁺ layers and perovskite blocks structures, BaBi₄Ti₄O₁₅ ferroelectric ceramic exhibits high breakdown strengthen, making it promising in energy storage applications. However, the substantial hysteresis and remnant polarization under electric field impairs its energy storage performance. In this work, rare-earth ion La³⁺ was added into BaBi₄Ti₄O₁₅ to form a new solid solution BaBi_4-xLa_xTi₄O₁₅ (BBLTx) to address the problem and simultaneously optimize the energy storage performance. Interestingly, the BBLTx ceramics demonstrated improved relaxor characteristic and reduced grain size, which significantly reduced the polarization hysteresis while increased the breakdown strength. Notably, the BBLT0.9 ceramic showcased high recoverable energy density of 6.7 J/cm³ and ultrahigh efficiency up to 93.5 %, under an applied electric field of 820 kV/cm. This work highlights the significant potential of BBT-based lead-free ceramics for advanced energy storage applications and provides novel insights into performance optimization strategies through functional modification.