Enhanced energy storage performance in SrTiO₃‐modified NBT‐based lead‐free ceramics via a stepwise strategy

Lead‐free dielectric ceramics are gaining prominence in energy storage due to their superior power density and rapid charge/discharge capabilities. However, Na 0.5 Bi 0.5 TiO 3 (NBT)‐based ceramics stand out as particularly promising dielectric materials, but face two critical challenges: excessive remnant polarization and inadequate dielectric strength, which substantially limit their energy storage performance. To enhance energy storage performance in lead‐free ferroelectric ceramics, a stepwise optimization method was adopted in this study. The strategy combines compositional engineering through precise elemental ratio adjustment to tailor microstructural characteristics, and processing optimization to significantly enhance breakdown strength ( E b ). This dual‐approach methodology has been experimentally demonstrated to effectively boost the energy storage capabilities of the ceramic system. The incorporation of SrTiO 3 as a modifier successfully induced nanoscale domain structures in the 0.91Na 0.5 Bi 0.5 TiO 3 ‐0.09K 0.7 La 0.1 NbO 3 (NBT‐KLN‐based) system, yielding desirable slim P ‐ E loops. Subsequently, the viscous polymer processing (VPP) technique was utilized to minimize defects and boost density, thereby significantly enhancing the E b . The optimized NBT‐KLN‐0.20ST‐vpp composite ceramics demonstrated remarkable energy storage properties, achieving a high W rec of 5.34 J/cm 3 and efficiency of 82% under 460 kV/cm. This study not only offers a viable strategy for improving NBT‐based ceramics but also lays the groundwork for designing advanced energy storage materials, demonstrating promising applications in compact power electronics.