In this work, the effects of dispersion of highly insulating/adiabatic SiO₂ aerogels on the microstructure and thermoelectric properties of BiCuSeO have been studied. The composited samples were prepared by high-temperature vacuum solid-state reaction, mechanical alloying, and spark plasma sintering. In order to analyze the influence of SiO₂ adhesion on the properties of BiCuSeO, we constructed the BiCuSeO/SiO₂ composite interface by Materials Studio software and carried out first principles calculation. The results showed that the dispersion of SiO₂ aerogels would reduce the density of states in the Cu 3d and Se 4p orbits of BiCuSeO matrix and correspondingly decrease the carrier concentration and electrical conductivity. However, the energy filtering effect caused by wide-bandgap SiO₂ aerogels dispersion and the decrease of carrier concentration would lead to the enhancement of the Seebeck coefficient. The lattice thermal conductivity decreases for that the highly insulating/adiabatic SiO₂ aerogels dispersed between BiCuSeO matrix gaps contribute to the phonons scattering. The thermal conductivity decreases due to the lattice thermal conductivity and the decrease of the electrical thermal conductivity. The highest ZT value has been increased to 1.20 at 873 K, which is 2.92 times of the pristine sample.

在这项工作中，研究了高绝缘/绝热 SiO ₂气凝胶的分散对 BiCuSeO 的微观结构和热电性能的影响。通过高温真空固相反应、机械合金化和放电等离子烧结制备复合样品。为了分析SiO ₂粘附对BiCuSeO 性能的影响，我们通过Materials Studio 软件构建了BiCuSeO/SiO ₂复合界面并进行了第一性原理计算。结果表明，SiO ₂的分散气凝胶会降低 BiCuSeO 基质的 Cu 3d 和 Se 4p 轨道中的态密度，并相应地降低载流子浓度和电导率。然而，宽带隙SiO ₂气凝胶分散引起的能量过滤效应和载流子浓度的降低会导致塞贝克系数的增加。由于分散在 BiCuSeO 基体间隙之间的高度绝缘/绝热 SiO ₂气凝胶有助于声子散射，晶格热导率降低。由于晶格热导率和电热导率的降低，热导率降低。最高 ZT 值在 873 K 时增加到 1.20，是原始样品的 2.92 倍。