Thermoelectric Cement Composite Materials for Energy Harvesting and Self-Powered Sensing.

Abstract

The share of building energy consumption in global total energy consumption continues to rise. Transforming building envelopes into media for low-grade heat harvesting and self-powered sensing has therefore become one of the key technological pathways toward achieving the "dual carbon" goals. In recent years, ionic thermoelectric (i-TE) materials have attracted widespread attention due to their operational capability under low temperature gradients, readily available raw materials, and high thermoelectric potential. Endowing commodity building materials with i-TE functionality offers an effective strategy for low-grade waste heat harvesting in buildings and their low-carbon transition. Cement-based materials, owing to their natural porous structure, abundant pore solution ions, and multiphase solid-liquid interfacial environment, exhibit unique potential as i-TE media. This paper systematically reviews the research progress on the i-TE performance of i-TE cement-based composites (i-TECs). The core mechanisms of the thermodiffusion effect and thermogalvanic effect are explained, and a framework for evaluating key performance parameters is established. The paper examines how the intrinsic properties of the cement matrix govern i-TE behavior and summarizes the strategies currently employed to optimize performance. The applications of i-TECs in building energy harvesting, self-powered temperature sensing, and structural supercapacitor energy storage are surveyed, highlighting the multifunctional potential of these materials. Finally, this review outlines the key challenges in guiding the rational development of durable and efficient i-TECs, and provides an outlook on the development prospects and engineering application potential.