Heat storage in form of chemical reaction potential is currently less widespread but is developing rapidly. The performance of thermochemical energy storage in terms of energy density (several hundred kWh/m3) and discharge time is comparable to pumped storage systems (hydroelectric or compressed air), which makes it the most promising energy storage option. The principle is based on a thermochemical system of adsorption/desorption of water molecules by hydrophilic salt powders, which is one of the least expensive variants with minimal environmental impact. However, salt powders have drawbacks in terms of mass (water vapor) and heat transfer problems. The loss of specific reaction surface area during the hydration cycles due to agglomeration of the crystalline salt particles may result in loss of storage capacity and poor cyclic stability.

To overcome these difficulties, we propose in our study the system of an open-pore metal foam as a host matrix containing salt crystallites. With an adapted structure, this system would facilitate the circulation of water vapor and heat generated in the system by isolating the salt particles to avoid agglomeration, thus to improve the performance of the thermochemical heat storage system.

In our study, we present the method of synthesizing the composite with open-pore Al, Ni, Cu foam and calcium chloride as salt. Then, the thermochemical properties of the composites are characterized with differential scanning calorimetry (DSC) through cyclic hydration/dehydration tests for evaluating its energy storage capacity and cyclic stability. In addition, in-situ hydration/dehydration tests are performed under the environmental scanning electron microscope (ESEM) for investigating the performance improvement mechanism of the composites. For study its mechanical properties, in-situ uniaxial pression tests are performed on metal foam. Micro-CT (micro computed tomography) is used for observation of the initial and final state of the metal foam before and after deformation. Finally, 3D-digital image correlation (DIC) technique is applied for computing and characterizing the macro and local deformation on three dimensions of the metal foam during compression test.