Present Status and Future Perspectives of Low‐Temperature Thermochemical Heat Storage Composite Materials for Higher Performance: A Comprehensive Review

This review focuses on thermochemical heat storage (TCHS) materials and their composites, aiming to enhance efficiency for low‐temperature applications. To obtain comprehensive information on the selection of suitable high‐performing TCHS materials, variousreports from past research were critically reviewed and systematically categorized. First, the application requirements, such as hydration energy storage density dataand working temperature requirements, were compiled and categorized for silica‐based composites, metal‐organic frameworks (MOFs), zeolite‐based composites, carbon‐based composites, metal foams, polymer‐based composites, hybrid composites, and advanced, modern, synthesized composite materials. These requirements were then critically reviewed. In addition to that, it was reminded that porous silica materials, MOFs, and zeolite materials can enhance the hydration sorption performance, providing a porous structure, while high conductive carbon materials are used to enhance heat transferring property during hydration/dehydration, and also polymer composites are usually used to stabilize as a binding material for enhanced cyclic stability by preventing agglomeration and delinquency at the state of overhydration. Then, after the working pair materials (adsorbates), such as water vapor, ammonia, alcohols, and other synthetic organic materials, were reviewed, the literature data were tabulated. Lastly, past works, present status limitations, and future standpoints are presented to identify the required working‐pair materials for the development and selection of suitable materials and a sorbent working pair for high‐energy‐density and precise operating conditions of the TCHS process.