Magnesium phosphate-based thermoelectric materials as an efficient, stable and scalable bulk power supply solution†

Combining thermoelectricity with construction materials can take advantage of the huge exposed surface of buildings, which is conducive to utilizing the low-grade portion of clean energy sources, such as solar and wind, to reduce fossil energy consumption. However, thermoelectric technologies are still facing balancing issues between high-performance, efficiency and expensive costs, complex processes, and difficulty in preparing large-scale devices. We choose inexpensive and abundant chemical precursors to prepare magnesium phosphate thermoelectric materials (MPTEMs) with a fitted Seebeck coefficient of up to 11.16 mV K⁻¹, solely via a mixing process. This is proven to arise from the selective thermal diffusion of ions from the pores of the magnesium phosphate matrix, and the electron/hole drift phenomenon of the carbon black network. The thermoelectric figure of merit and power factors of the MPTEMs can exceed 0.52 and 1513 μW m⁻¹ K⁻², respectively, which are 51 and 42 times more than the highest records of existing thermoelectric construction materials. Furthermore, the MPTEMs can achieve stable and continuous discharge, and their thermoelectric properties can be upgraded by assembling and expanding continually. This means they could be used to build large-scale self-powered infrastructure in the future.