Thermochemical energy storage in barium carbonate enhanced by iron(iii) oxide

Renewable energy requires cost effective and reliable storage to compete with fossil fuels. This study introduces a new reactive carbonate composite (RCC) where Fe2O3 is used to thermodynamically destabilise BaCO3 and reduce its decomposition temperature from 1400 degrees C to 850 degrees C, which is more suitable for thermal energy storage applications. Fe2O3 is consumed on heating to form BaFe12O19, which is a stable Fe source for promoting reversible CO2 reactions. Two reversible reaction steps were observed that corresponded to, first, the reaction between beta-BaCO3 and BaFe12O19, and second, between gamma-BaCO3 and BaFe12O19. The thermodynamic parameters were determined to be Delta H = 199 +/- 6 kJ mol(-1) of CO2, Delta S = 180 +/- 6 J K-1 mol(-1) of CO2 and Delta H = 212 +/- 6 kJ mol(-1) of CO2, Delta S = 185 +/- 7 J K-1 mol(-1) of CO2, respectively, for the two reactions. Due to the low-cost and high gravimetric and volumetric energy density, the RCC is demonstrated to be a promising candidate for next generation thermal energy storage.

Automated summary

This study introduces a new reactive carbonate composite (RCC) that uses Fe2O3 to destabilize BaCO3 and reduce its decomposition temperature, making it more suitable for thermal energy storage. The RCC demonstrates promising potential for next-generation thermal energy storage due to its low cost and high energy density. The thermodynamic parameters for the reversible CO2 reactions were determined and found to be significant for the RCC.