Structural, dielectric, ferroelectric and energy storage properties of 0.58BFO–0.3BTO–0.12NNO + x wt% CBSKN ceramics

Lead-free BiFeO ₃ –BaTiO ₃ (BFO–BTO) materials with giant spontaneous polarization and high Curie temperatures exhibit considerable potential for innovative applications in dielectric capacitor. However, their intrinsic drawbacks, including low electric breakdown strength and low recoverable energy storage density ( W _reco ), severely limit their energy storage capabilities. In the present study, a strategy of introducing Ca/B/Si/K _0.01 /Na _0.02 (CBSKN) glass-phase liquid sintering into BFO-BTO ceramics is put forward to improve their breakdown strength and recoverable energy storage density. Ceramics with the composition 0.58BiFeO ₃ –0.3BaTiO ₃ –0.12NaNbO ₃  +  x wt% Ca/B/Si/K _0.01 /Na _0.02 were prepared using the traditional high-temperature solid-state reaction method. The incorporation of CBSKN glass powder leads to a reduction in the Δ P ( P _max – P _r ) value of the samples, whereas an appropriate doping content can effectively enhance the electrical breakdown strength of the ceramics. Calculations of energy storage properties show that the CBSKN05 ceramic achieves a maximum energy storage density of 2.13 J/cm ³ under an electric field of 190 kV/cm. Finally, the energy storage stability of CBSKN05 ceramics was evaluated under 100 kV/cm at various temperatures and frequencies, which indicating the incorporation of glass powder is helpful to improve thermal and frequency stability for energy storage applications. These results suggest that 0.58BFO–0.3BTO–0.12NNO ceramics modified with CBSKN glass are promising candidates for high-density energy storage devices.