Ferro-alloys as high temperature phase change materials

• Ferro-alloys, particularly Fe–Si–Ti compositions, achieve energy storage capacities up to 1.5 MWh·m−3, exceeding the 1 MWh·m−3 target for high-temperature LHTES. • The Fe–Si–B system shows high latent heat due to boron, but its high melting point and cost limit practical application. • Fe–Si–Cr alloys like Fe–34Si–38Cr and Fe–34Si–43Cr offer excellent energy storage density and favorable phase transition temperatures. • Thermodynamic assessment using FactSage identifies promising ferro-alloy PCMs for operation above 1000°C, outperforming some state-of-the-art metallic PCMs.