OXITES · Experimental and computational screening of Oxides for Thermochemical Energy Storage (OxiTES)

Renewable and sustainable energy systems of the future are only possible in combination with storage technologies for bridging the gap between production and consumption of energy. The use of solar energy is inherently limited by the intermittency of solar light which requires robust and efficient solutions for energy storage. One of the attractive storage options for large-scale solar systems is ThermoChemical Energy Storage (TCES) based on the use of reversible chemical reactions. TCES combines high heat storage density with unlimited storage duration, endowing the energy storage efficiency and flexibility. Currently, the number of materials studied for TCES at high temperatures remains very limited, hindering further development of thermochemical systems. The project is aimed at the search for promising TCES materials among oxides of earth-abundant metals by combining experimental and theoretical studies. First, a longlist of promising oxide candidates (< 200) will be generated based on structural databases. Then, the experimental screening will be done to outline conditions for their hydration and carbonation reactivity and measurement of relevant parameters such as sorption capacity and heat. The theoretical study bridging DFT calculations with the experimental data by means of machine learning will highlight the structure-property relationship for the broad set of oxides. Finally, several most promising materials with high storage density will be tested in a prototype of chemical heat pump operating at T = 300-600oC. As a result, a library of promising oxides for high-temperature H2O and CO2 sorption will be generated and theoretical guidelines for future target-based development of oxide systems for this purpose will be delivered. This project realized within DLR (Germany) in cooperation with Delft University of Technology (Netherlands) will bring the TCES closer to market scale. The idea is in line with the current EU policy towards renewable energy.