Defect controlling of BaTiO3@ NiO double hysteresis loop ceramics with enhanced energy storage capability and stability

Dielectric capacitor with high energy storage density has become a pivotally enabling technology in electronic industry. The most critical factors affecting energy storage capacity are polarization and breakdown strength . Here the BaTiO 3 @ NiO double-hysteresis-loop ceramics with different polarization characteristics are prepared by changing the sintering atmosphere to control the defect structure . Results show that, the samples sintered in oxygen exhibit the obviously characteristics of double hysteresis loop, higher polarization and larger breakdown strength . In contrast, the samples sintered in nitrogen have lower polarization and breakdown strength and weaker double hysteresis loop. It is proved that the double hysteresis loop is caused by the defects of the inner layer and the outer layer by regulating the defect structure . Firstly, Low valence Ni ions replace Ti ions to form N i Ti '' − V o • • $\left(\text{N}{\text{i}}_{\text{Ti}}^{\text{''}}-{\text{V}}_{\text{o}}^{••}\right)$ defect dipoles. These charged defect dipoles could be pinned the domain wall, and the existence of oxygen vacancies restricts the movement of the domain wall, making the material appeared a pinched hysteresis loop similar to the double hysteresis loop as observed in antiferroelectrics. Secondly, the local electric field generated by the depletion layer at the interface may also trigger a new polarization features in the material. This double hysteresis loop helps to improve the polarization and energy storage capacity of the material.Finally, the excellent energy storage density of the oxygen samples reaches up to 2.48 J cm −3 at 340 kV cm -1 with prominent cycle stability and temperature stability. This work provides a prospective method to fabricate material with high energy storage performance by the adjustment defect structure to control the polarization mechanism in the BaTiO 3 @1NiO ceramics.