Ab Initio and Experimental Investigation of Thermoelectric Properties in a Silica-Based Superinsulating Material

Abstract

Thermoelectric (TE) materials have drawn enormous research interest for decades as the TE effect facilitates direct conversion of heat into electrical energy or vice versa, thereby providing an alternative for power generation/refrigeration. However, the lack of TE materials that are simultaneously inexpensive, nontoxic, and efficient limits their industrial utilization. A new approach to address this challenge could be the electrical functionalization of commercially used─nontoxic, sustainable, lightweight, and low-cost─thermal superinsulating materials, e.g., Aerosil200, by doping. In the present work, as a first step toward this approach, we employ density functional theory calculations through the Vienna ab initio simulation package to create and validate a numerical model of pure Aerosil200. This was followed by the calculation of its electronic structure as well as TE properties using the BoltzTrap code. The calculated Seebeck coefficient and electrical conductivity, and thereby the power factor, showed excellent agreement with the experimentally determined values. Our numerical model, therefore, paves the way for further improvement of the power factor, hence ZT, through doping of Aerosil200 while retaining its low thermal conductivity.