Recent growth and potential applications of metallic phase change materials - A review

Thermal energy storage (TES) is vital for decarbonizing power generation and industrial processes, yet conventional phase change materials (PCMs)—such as paraffin waxes, fatty acids, salt hydrates, sugar alcohols—suffer from low thermal conductivity, phase segregation, supercooling, poor cycling stability and low decomposition temperature, limiting their use approximately above 300 °C. Metallic PCMs (unitary metals and multi-component alloys) are promising alternatives owing to their high thermal conductivity (up to ∼160 Wm⁻¹ K⁻¹ for AlSi12), large latent heat (up to 960 Jg⁻¹ for 17Al-53Si-30Ni), and superior stability. This review employs a two-phase methodology: (i) a systematic survey of recent studies to classify metallic PCMs by melting range (low, medium, and high temperature) and composition (unitary, binary, ternary, quaternary), and (ii) an application-oriented analysis mapping their performance across waste heat recovery, solar power, fuel cells, heat sinks, and electronic cooling. Among the collected alloys, representative alloys such as 17Al-53Si-30Ni (∼960 Jg⁻¹ of latent heat, ∼48 Wm⁻¹ K⁻¹ of thermal conductivity at 700 °C) and Al[sbnd]Si (∼560 Jg⁻¹ latent heat, ∼160 Wm⁻¹ K⁻¹ of thermal conductivity) highlight the potential of metallic PCMs for medium- to high-temperature TES. The analysis identifies Al[sbnd]Si and Mg[sbnd]Zn alloys as especially viable for concentrated solar power and industrial waste-heat recovery, while gallium-based alloys excel in low-temperature electronics cooling. Persistent challenges—oxidation, corrosion, and cost—underline the need for improved encapsulation strategies and alloy design. Unlike earlier fragmented reviews, this work uniquely consolidates thermophysical data, encapsulation advances, and application case studies, providing a clear roadmap for deploying metallic PCMs in next-generation TES systems.