Temperature stable (1-x)(0.9Na_0.5Bi_0.5TiO₃-0.1BiAlO₃)-xNaTaO₃ ceramics and capacitors with ultra-wide operational range

Temperature stable multilayer ceramic capacitors (MLCCs) are urgently required for electronic equipment applications. In this work, NaTaO₃ modified (1-x)(0.9Na_0.5Bi_0.5TiO₃-0.1BiAlO₃) ceramics (NBT-10BA-100xNT) were designed and fabricated. The effects of NaTaO₃ concentration on the dielectric properties, insulating properties, and energy storage properties were investigated. At the optimum composition of x = 0.25, stable permittivity (Δε^′/ε_25°C^′≤±15%) and low dielectric loss (tanδ≤ 0.02) over a wide temperature range of −100–334 °C were achieved. Furthermore, NBT-10BA-25NT based MLCCs with 70Ag/30 Pd inner electrodes were successfully fabricated by tape-casting method, which also exhibited both stable permittivity (Δε^′/ε_25°C^′≤±15%) and low dielectric loss (tanδ ≤ 0.02) in an ultra-wide temperature range (−100–398 °C). These excellent performances suggest that NBT-10BA-25NT could be a promising candidate of dielectrics with ultra-wide operational temperature range for MLCCs.