Research Progress and Key Technical Barriers in CaO/Ca(OH)₂ Based Energy Storage: A Systematic Review

The CaO/Ca(OH)₂ thermochemical energy storage system has garnered significant attention due to its cost-effectiveness, abundant raw material availability, optimal decomposition thermodynamics, high energy density, and recyclability as a promising candidate for large-scale renewable energy integration. Significant progress has been made in the research field of the CaO/Ca(OH)₂ energy storage system, while there are still key issues that require further investigation. This comprehensive review summarizes recent advancements in CaO/Ca(OH)₂ thermochemical energy storage systems, focusing on reaction mechanism and optimization through material engineering strategies, thermal-fluid dynamics in reactor configurations, cyclic degradation mechanisms under operational stresses, and scalability constraints in system integration. Persistent technical bottlenecks requiring resolution are discussed, particularly sintering-induced capacity decay and suboptimal heat transfer efficiency. The reactor design and optimization with advanced material modification techniques targeting enhanced stability are introduced as well. These discussions and derived suggestions provide a potential opportunity to bridge fundamental material science discoveries with engineering implementation for enabling deployment in stable utilization of renewable energy.