Colossal permittivity in high-entropy CaTiO3 ceramics by chemical bonding engineering
Jinghan Cai, Shun Lan, Bin Wei, Junlei Qi, Ce‐Wen Nan, Yuanhua Lin
Abstract
Dielectrics with high permittivity, low dielectric loss, and good temperature stability are crucial for electronic components to meet the ever-increasing application demands. However, challenges remain in further optimizing dielectric properties due to the correlation between these parameters. Here, we propose a chemical bonding engineering strategy in high-entropy CaTiO3 ceramics and realize colossal permittivity with low loss and excellent stability. Our results reveal that the high-concentration oxygen vacancy ( $${{{\rm{V}}}}_{{{\rm{O}}}}^{\cdot \cdot }$$ )-related defects and the decreased activation energy of grain/grain boundary led to a colossal permittivity dielectric behavior, which should be ascribed to the weakened chemical bonding and the reduced formation energy of defects confirmed by our first-principles calculation. Consequently, in the high-entropy CaTiO3 ceramic, a permittivity of 2.37 × 105, low loss of 0.005, and good temperature stability (<± 15%) in -50–250 °C are simultaneously achieved. This finding implies that chemical bonding engineering may be a promising strategy for designing colossal permittivity materials and provides a broad opportunity for the development of other defect-dependent functional materials. A chemical bonding engineering strategy is proposed in this work to realize the improvement of dielectric performance. A colossal permittivity of 2.37 × 105 and a low loss of 0.005 are ultimately achieved in high-entropy CaTiO3-based ceramics.