Fabrication of structure-improved, sintering-resistant Li4SiO4 materials for stabilized thermochemical energy storage in concentrated solar power plants

Thermochemical energy storage has been considered as a promising technology for the future high-temperature solar thermal conversion and utilization in concentrated solar power plants. In this work, Li 4 SiO 4 /CO 2 thermochemical energy storage system was designed based on the reversible reaction Li 4 SiO 4  + CO 2 ↔Li 2 SiO 3  + Li 2 CO 3 . The proposed Li 4 SiO 4 -based system, which possesses a heat releasing temperature of ∼700 °C, fills in the gaps of medium temperature TCES materials. Furthermore, structure-improved, sintering-resistant Li 4 SiO 4 materials with stabilized performance were fabricated by using organic lithium precursor and cerium addition, and corresponding enhancement mechanisms were systematically studied. It is concluded that the utilization of lithium salicylate could effectively improve the surface morphology as well as the specific surface area of Li 4 SiO 4 particles. And the Ce addition could enhance the cyclic stability of Li 4 SiO 4 by forming anti-sintering CeO 2 fine particles inside. As a result, the obtained L-S-Ce2.5 exhibits an average capacity of 671.3 kJ/kg with the capacity decay as low as 13 kJ/kg per cycle, which is of great significance for the practical long-term heat storage/releasing applications at medium temperature.