Despite higher dielectric constants than nonpolar polymers, polar polymers exhibit a high dielectric loss, which is detrimental for electric energy storage applications. To mitigate the ionic conduction loss, we have fabricated multilayer films (MLFs) with alternating layers of a high dielectric constant polar polymer and a high breakdown/low loss nonpolar polymer. In this study, we fabricated high temperature polycarbonate (HTPC)/poly (vinylidene fluoride) (PVDF) MLFs. The ionic transport behavior confined in the PVDF nanolayers under a low electric field was investigated using broadband dielectric spectroscopy (BDS). Direct analytical simulation was implemented to determine the concentration (n₀) and diffusion coefficient (D₀) for the confined impurity ions in PVDF at different temperatures and with and without the presence of lamellar crystals. It was found that both n₀ and D₀ increased upon increasing temperature. Using the simulated n₀ and D₀, nanoconfined transport of impurity ions was found for the PVDF layers with decreasing the layer thickness. Namely, a crossover PVDF layer thickness was predicted, below which the conduction loss from impurity ions substantially decreased. However, experimental BDS results systematically deviated from the theoretical predictions. One important reason for this deviation was attributed to the presence of edge-on lamellar crystals confined in the PVDF layers, which increased the tortuosity of the ion transport pathway. The knowledge gained in this study can be useful to understand the nanoconfinement and crystallinity effects on the ionic transport in MLFs, which is beneficial for the future development of MLFs for capacitor applications.

尽管介电常数比非极性聚合物高，但极性聚合物仍表现出高介电损耗，这对电能存储应用有害。为了减轻离子传导损耗，我们制作了多层膜（MLF），其中的交替层是高介电常数极性聚合物和高击穿/低损耗非极性聚合物。在这项研究中，我们制造了高温聚碳酸酯（HTPC）/聚偏二氟乙烯（PVDF）MLF。使用宽带介电谱（BDS）研究了在低电场下限制在PVDF纳米层中的离子迁移行为。通过直接分析模拟确定浓度（n ₀）和扩散系数（D ₀）在不同温度下以及有无层状晶体存在下PVDF中的受限杂质离子。发现n ₀和D _0都随温度升高而增加。使用模拟的n ₀和D ₀，随着层厚度的减小，发现了PVDF层的杂质离子的纳米限制传输。即，预测了跨越PVDF层的厚度，在该厚度之下，来自杂质离子的传导损耗显着降低。但是，实验性BDS结果系统地偏离了理论预测。造成这种偏离的一个重要原因归因于在PVDF层中封闭的边缘层状晶体的存在，这增加了离子传输路径的曲折性。在这项研究中获得的知识可能有助于理解纳米限制和结晶度对MLFs中离子迁移的影响，这对于电容器应用MLFs的未来发展是有益的。