xBi_2/3Cu₃Ti₄O₁₂/(1-x)CaCu₃Ti₄O₁₂ composites were prepared by traditional solid-state reaction method. Extremely high nonlinear coefficient of 25 and breakdown field of 18.92 kV·cm⁻¹ were obtained in small current range of 0.1−1 mA·cm^-2. In addition, reduced dielectric loss of 0.055 was achieved with high dielectric constant of 1369. Optimized nonlinear and dielectric properties were integrated to make the composites a promising dual-function varistor-capacitor candidate. Microstructure analysis discovered two areas with various Bi/Ca ratio, designated as Bi-H and Bi-L respectively. It was found that the maximum ratio of Bi-H/Bi-L heterogeneous interface corresponded to optimized nonlinear and dielectric performance, which was associated with elevated potential barrier height and huge grain boundary resistance. Combined with relaxation analysis, a core-shell structure was proposed to elaborate microstructure evolution in xBi_2/3Cu₃Ti₄O₁₂/(1-x)CaCu₃Ti₄O₁₂ composite. According to the core-shell model, variation of heterogeneous interface was illustrated on how to influence nonlinear properties, which was well fitted to experimental results.

采用传统的固相反应法制备了x Bi _2/3 Cu ₃ Ti ₄ O ₁₂ /（1- x）CaCu ₃ Ti ₄ O ₁₂复合材料。在0.1−1 mA·cm ^-2的小电流范围内获得了极高的25非线性系数和18.92 kV·cm ^-1的击穿场。此外，在1369的高介电常数的情况下，介电损耗降低了0.055。优化的非线性和介电性能综合在一起，使该复合材料成为有希望的双功能压敏电容器候选者。微结构分析发现了两个具有不同Bi / Ca比的区域，分别称为Bi-H和Bi-L。发现Bi-H / Bi-L异质界面的最大比例对应于优化的非线性和介电性能，这与提高的势垒高度和巨大的晶界电阻有关。结合弛豫分析，提出了一种核-壳结构来详细描述x Bi _2/3 Cu ₃ Ti ₄ O _12中的微观结构演变。/（1- x）CaCu ₃ Ti ₄ O ₁₂复合材料。根据核-壳模型，说明了异质界面如何影响非线性特性的变化，非常适合实验结果。