Polymer-based nanocomposites always exhibit excellent energy storage capacity and have a great potential to be used in the field of electrical equipment and electronic device. In this study, the Ba_xSr_1-xTiO₃ nanoparticles wrapped with SiO₂ (Ba_xSr_1-xTiO₃@SiO₂) are chosen as inorganic nanofillers and filled into the poly(methyl methacrylate) (PMMA) matrix. The intrinsic properties of inorganic fillers, including phase composition, dielectric properties, breakdown strength and polarization behavior, on the energy storage performances of polymer-based nanocomposites have been systematically investigated. Especially, the fillers with ferroelectric phase composition will be polarized when they are subjected to a local electric field, leading to the changed dielectric constant, this factor is considered to analyze the electric field distribution for the first time. The results show that the optimized phase composition of Ba_xSr_1-xTiO₃ enables the nanocomposites to possess synergistically improved breakdown strength and polarization, giving rise to the excellent energy storage performances, where an energy storage density of 19.6 J/cm³ and an efficiency of 74.4% for 1 vol% Ba_0.6Sr_0.4TiO₃@SiO₂/PMMA nanocomposites. This study provides a valuable way to select appropriate inorganic fillers and optimize energy storage performances of polymer-based nanocomposites.

基于聚合物的纳米复合材料始终展现出出色的储能能力，并且在电气设备和电子设备领域具有巨大的潜力。在这项研究中，Ba _x Sr _{1- x} TiO ₃纳米颗粒包裹了SiO ₂（Ba _x Sr _{1- x} TiO ₃ @SiO ₂选择）作为无机纳米填料，然后填充到聚甲基丙烯酸甲酯（PMMA）基质中。已经系统地研究了无机填料的固有性质，包括相组成，介电性质，击穿强度和极化行为，对聚合物基纳米复合材料的储能性能。尤其是，具有铁电相组成的填料在受到局部电场作用时会极化，导致介电常数发生变化，首次考虑该因素是分析电场分布的原因。结果表明，Ba _x Sr _{1- x} TiO ₃的最佳相组成使纳米复合材料具有协同改善的击穿强度和极化性能，从而带来出色的能量存储性能，其中能量存储密度为19.6 J / cm ³，而1 vol％Ba _0.6 Sr _0.4 TiO ₃ @SiO的效率为74.4％₂ / PMMA纳米复合材料。这项研究提供了一种宝贵的方法，可以选择合适的无机填料并优化聚合物基纳米复合材料的储能性能。