Structure, dielectric properties of low-temperature-sintering BaTiO3-based glass–ceramics for energy storage

Abstract

The 0.85BaTiO3–0.15Bi(Mg2∕3Nb1∕3)O3 (BTBMN) ceramics with low-melting-temperature B2O3–Na2B4O7–Na2SiO3 (BNN) glass addition were prepared by the solid state method. The composition of the glass–ceramics was BTBMN–x wt.% BNN (x=0, 1, 3, 5, 7, 9, 12, 15; abbreviated as BG). The sintering characteristics, phase structure, microstructure, dielectric properties and energy storage properties were systematically investigated. The sintering temperature of BTBMN ceramics was greatly reduced by the addition of BNN glass. The second-phase BaTi(BO3)2 was observed in the BG system until the glass content reached 15wt.%. The addition of BNN glass significantly reduces the grain size of BTBMN ceramics. With the increase of BNN glass content, dielectric constant of BG glass–ceramics at 1kHz gradually decreased, the maximum dielectric constant (εm) of BG glass–ceramics gradually decreased, while the temperature corresponding to the maximum dielectric constant (Tm) increased, the ferroelectric relaxation behavior decreased and the temperature stability of the dielectric constant gradually improved. As the BNN glass content increased, the breakdown electric field strength (BDS) of BG glass–ceramics increased first and then decreased, and the polarization values reduced gradually, while the trend of energy storage performance is similar to BDS. When the BNN glass content was 3wt.%, the energy storage properties of the BG glass–ceramics were optimal, and a recoverable energy storage density (Wrec) of 1.26J/cm3 and an energy storage efficiency (η) of 80.9% were obtained at the electric field strength of 220kV/cm. The results showed that BG glass–ceramics were promising for energy storage capacitors.

Keywords

• Lead-free
• glass–ceramics
• BaTiO3
• relaxation
• energy storage properties