We present a novel approach to reduce the thermal conductivity ($k$) in thermoelectric composite materials using acoustic impedance mismatch and the Debye model. Also, the correlation between interface thermal resistance ($R_{int}$) and the particle size of the dispersed phase on the $k$ of the composite is discussed. In particular, the $k$ of an oxide composite, which consists of a natural superlattice Aurivillius phase (SrBi₄Ti₄O₁₅) as a matrix and perovskite (La_0.7Sr_0.3MnO₃) as a dispersed phase, is investigated. A significant reduction in $k$ of composite, even lower than the $k$ of the matrix when the particle size of La_0.7Sr_0.3MnO₃ is smaller than the Kapitza radius ($a_K)$ is observed, depicting that $R_{int}$ dominates for particle size lower than $a_K$ due to increased surface to volume ratio. The obtained results have the potential to provide new directions for engineering composite thermoelectric systems with desired thermal conductivity and promising in the field of energy harvesting.

我们提出了一种降低热导率的新颖方法（$ķ$）在热电复合材料中使用声阻抗失配和Debye模型。而且，界面热阻之间的相关性（${\mathrm{[R}}_{\mathrm{一世}ñŤ}$）和分散相的粒径 $ķ$复合材料的讨论。特别是$ķ$研究了由天然超晶格Aurivillius相（SrBi ₄ Ti ₄ O ₁₅）作为基质和钙钛矿（La _0.7 Sr _0.3 MnO ₃）作为分散相组成的氧化物复合材料的结构。大大减少$ķ$ 的复合材料，甚至低于 $ķ$当La _0.7 Sr _0.3 MnO ₃的粒径小于Kapitza半径（${\mathrm{一种}}_{ķ}）$ 被观察到，描绘了 ${\mathrm{[R}}_{\mathrm{一世}ñŤ}$ 粒径小于 ${\mathrm{一种}}_{ķ}$由于增加了表面体积比。获得的结果有可能为工程复合热电系统提供新的方向，该系统具有所需的热导率，并且在能量收集领域很有希望。