Suitable solid filler materials are investigated for use in a packed‐bed heat storage test facility for high temperatures with lead–bismuth eutectic (LBE) as the heat transfer fluid. Accordingly, first, the thermophysical properties of six different candidate materials, two glasses and four ceramics, are determined. The density and heat capacity are measured experimentally and the thermal conductivity is discussed based on literature data. Subsequently, a static corrosion test is performed at 500 °C for 1 and 4 weeks in LBE under reducing conditions. The glasses are found to be unsuitable due to corrosion attack. Among the ceramics, zirconium silicate and zirconium oxide are identified to be highly resistant to corrosion. Zirconium silicate is subsequently also successfully tested as a storage material in a laboratory experiment under cyclic conditions.