Magnesium Compounds for Chemical Heat Storage: A Review

Magnesium compounds such as , , , , and are promising candidates for chemical heat storage (CHS) due to their high energy density, low cost, and practical applicability, especially in large‐scale or long‐term systems. This review summarizes key developments in magnesium‐based CHS from 2020 to 2025. Materials are classified by operating temperature: high (>600 °C), medium (200–600 °C), and low (<200 °C). Recent efforts focus on enhancing material performance through multicomponent doping, matrix support, and molecular structure design to overcome limitations like low thermal conductivity and phase instability. For example, Mg doping reduces the reaction time in Cr‐redox CHS by 3.7 times. In the medium‐temperature range, NaOH and LiCl lower the dehydration temperature of to 230 °C. At low temperatures, loading and on porous matrices improves heat/mass transfer and cycling stability. Several CHS reactors have been demonstrated, the largest reaching 47.9 m 3 , but device‐level optimization remains underexplored. Future research should emphasize mechanism‐driven material design, machine learning, reactor simulation, and scale‐up. This review provides a concise overview of recent progress and future directions to support practical CHS deployment.