Study on Corrosion and Thermal Alteration of Low‐Cost Storage Materials for Use in High‐Temperature Thermal Energy Storage Systems With Lead as the Heat Transfer Fluid

ABSTRACT Liquid metal packed‐bed thermal energy storage (TES) can improve industrial waste heat recovery due to its wide operating temperature range and high thermal conductivity. However, reducing costs, especially for storage media, is essential for broader adoption. Until now, no experimental analysis of low‐cost material in contact with liquid metal at high temperatures has been investigated in detail. Therefore, this study focuses on natural and waste materials as packed bed materials for high‐temperature TES systems using lead as the HTF. Two steel slags (from an electric arc furnace and a basic oxygen furnace) and four natural materials (basalt, red brick, iron pellets, magnetite) were selected as promising candidates due to suitable thermal properties and low material costs. They were exposed to static lead at 750°C for 1008 h to assess their compatibility with the HTF. After exposure, all samples showed degradation or phase transformation. Steel slag performed best with only minor lead attack on the Mg‐Fe oxide phases. Diopside in basalt was concluded to be stable in lead, but nepheline, also present, appeared to have reacted with Pb. In brick, the main component, quartz, was found to be stable in lead, but impurities and trace elements in the sample reacted with lead. Magnetite and iron pellets had the most severe degradation, forming deep cracks due to phase transformation at high temperatures.