Abstract
Calcium-based materials (CaCO3/CaO) have shown significant potential for use in thermochemical energy storage systems for concentrated solar power generation due to their low-cost, high-energy storage efficiency, and operational temperature range. However, the energy storage performance of calcium-based heat carriers degrades rapidly over cycles due to high-temperature sintering, limiting practical applications. In this study, we incorporated Zr into CaO using both heat-drying and freeze-drying methods, forming CaZrO3 as a physical barrier to prevent agglomeration and sintering of calcium particles at elevated temperatures. Experimental results demonstrated that Zr incorporation markedly improved cyclic energy storage stability, particularly for heat carriers derived from freeze-drying. Cao incorporated with 10 % CaZrO3 (FD-Zr10) showed a high energy storage density of 2161.75 kJ/kg over ten storage/release cycles, which was 25.89 % higher than that of pure CaO sample. Even over an extended operation of 30 cycles, FD-Zr10 still possessed the high energy storage density of 1939.76 kJ/kg. CO2-containing harsh storage conditions caused more sintering for the heat carriers, thus resulting in the performance reduction, but FD-Zr10 performed much better than other samples in resisting sintering. Various characterization analyses were conducted to investigate the reasons for the samples’ cyclic stability. It was discovered that freeze-drying incorporation generated a dendritic surface with a more abundant pore structure, and the incorporated CaZrO3 functioned as a metal skeleton to mitigate high-temperature sintering.
Feng, Q., Hu, Y., Liu, D., & Fu, R. (2024). Incorporation of CaZrO3 into calcium-based heat carriers for efficient solar thermochemical energy storage. Solar Energy Materials and Solar Cells, 266, 112700. https://doi.org/10.1016/j.solmat.2024.112700
