Boosting extraordinary energy-storage in BaTiO3-based ferroelectric ceramics via surface reconstruction cation-defects engineering

Abstract

Lead-free relaxor ferroelectrics (RFEs) have great potential applications in dielectric ceramic capacitors due to their distinguished energy storage performance, such as power pulse devices, manufacturing motors, sensors, and more. However, achieving high energy density and high efficiency simultaneously is a major challenge for practical applications. The performance of a capacitor depends largely on the interface between metal electrode and ceramics, which is related to the transfer of charge carrier process. In this work, the relaxation degree and defect dipole are manipulated by entropy manipulation and cation defect, while the surface micro-region area defect control is caused by the surface buried firing calcination process. We have designed and synthesized the performances of all the series of BaTiO₃-basedperovskite ceramics as well as surface cation defect modification such as BaTiO₃, Ba_0.95TiO₃, (Ba_0.95Sr_0.05)TiO₃, (Ba_0.95-3x/2Sr_0.05Bi_x)TiO₃, resurfaced (Ba_0.95Sr_0.05)TiO₃, and resurfaced (Ba_0.95-3x/2Sr_0.05Bi_x)TiO₃. Surface micro-region lattice distortions caused by the surface cation-defects reduce the carrier diffusion between the metal electrode and the BaTiO₃-basedperovskite ceramic samples, which diminishes the polarization hysteresis and improving the energy storage efficiency. Specifically, the surface reconstructed (Ba_0.8Sr_0.05Bi_0.1)TiO₃ ceramics exhibited excellent breakdown field strength characteristics (E_b = 155 kV·cm⁻¹) and minimal hysteresis residual polarization characteristics (P_r = 1.9 μC·cm⁻²), resulting in the largest storage density (W_rec = 1.193 J/cm³) and highest efficiency (η = 83.41%), indicating the general efficacy of our surface cation-defects engineering strategy, which provided new insights for the design of ceramic components.