A comprehensive and updated review is provided in this article, with a focus on water sorption-based thermochemical storage (WSTCS) materials, covering materials and their manufacturing routes. The state of the art of 22 most relevant salt hydrates is classified into seven groups (bromides, sulphates, carbonates, chlorides, nitrates, hydroxides, and sulphides) and studied as candidates. This is followed by a discussion on TCS material manufacturing, covering both conventional (shaping, pelletizing, etc.) and more advanced routes (e.g., extrusion, 3D printing, encapsulation, etc.). Finally, concluding remarks are presented, including limitations and future potentials for TCS research.

This review presents a technology roadmap for Thermal Energy Storage (TES) systems operating in the medium-temperature range of 100–300 °C, a critical window that accounts for approximately 37% of industrial process heat demand in Europe. Decarbonising this segment is essential to meeting climate targets, especially in sectors that are reliant on fossil-fuel-based steam. The study analyses 11 TES technologies, including sensible, latent, and thermochemical systems, covering both mature and emerging solutions. Each technology is evaluated based on technical, environmental, and socio-economic key performance indicators (KPIs), such as energy density (up to 200 kWh/m³), cost per storage capacity (€2–100/kWh), and technological readiness level (TRL). Sensible heat technologies are largely mature and commercially available, while latent heat systems—especially those using nitrate salts—offer promising energy density and cost trade-offs. Thermochemical storage, though less mature, shows potential in high-cycle applications and long-term flexibility. The review highlights practical configurations and integration strategies and identifies pathways for research and deployment. This work offers a comprehensive reference for stakeholders aiming to accelerate industrial decarbonisation through TES, particularly for applications such as drying, evaporation, and low-pressure steam generation.

Major advancements are needed in the thermochemical energy storage (TCES) field to bring the technology to commercial levels. The current research strategies are focused on improving heat and mass transfer using different supporting materials to achieve mechanical integrity during storage. However, these strategies are still under development, and they have not overcome the lab scale yet. This work explores novel matrices to expand the material database for TCES composites. Pure structural matrices (cellulose) and novel matrices with storage potential (polymeric solid–solid phase change materials) are selected and combined with three well‐known thermochemical materials (TCMs) (MgSO₄·6H₂O, SrBr₂·6H₂O and MgCl₂·6H₂O), providing evidence of hybridized composites with storage capacity up to 2.4 GJ m⁻³ with a 25–20 wt% of polymeric matrix. The polymer content is found to act as a nucleating agent in the magnesium sulfate crystallization process forming a synthetic monohydrate crystalline phase (Kieserite) and inhibiting the formation of the amorphous phase. The effect of the matrix is proved to induce certain structural deformation or changes not observed in the pure TCM sorption process. This phenomenon has the potential to benefit the stabilization of the TCM, e.g., inhibition of the formation of amorphous phase in magnesium sulfate composites.

Concentrated Solar Power (CSP) enables stable, dispatchable electricity generation through an integrated Thermal Energy Storage (TES) system, but current molten salt-based configurations are limited to ~565ºC, constraining efficiency and system integration. The COOPERANT project develops a novel high-temperature CSP-TES system operating up to 1,000ºC, combining advanced volumetric receivers, hybrid sensible-latent storage, and AI-based digital control. This approach enables coupling with next-generation power cycles such as supercritical steam Rankine, air Brayton and supercritical CO2 (sCO2) cycles, while addressing the challenges of component durability, cost, and sustainability. By integrating innovative materials, digital twins, and circular design principles, COOPERANT aims to enhance the efficiency, scalability, and commercial viability of CSP, contributing to a resilient and decarbonized energy system.