Understanding thermochemical energy storage performance of Ba 1-x Sr x CoO 3-δ perovskite system: A computational and experimental study

Concentrated solar power coupled with thermochemical energy storage (TCES) has emerged as an effective approach for renewable energy utilization. TCES based on perovskites attracts much attention because of temperature tunability and high flexibility. In this work, the electronic structures are simulated by the density functional theory (DFT) method, revealing the reduction temperatures is related to the formation energy of oxygen vacancy (E vac ). The compounds of Ba 1-x Sr x CoO 3-δ with x  = 0–1 are synthesized and investigated by experimental methods. According to the results, Ba content improves the redox capacities and reaction kinetics, while Sr content expands the reaction temperatures and enhances the micro morphologies. In addition, all the samples present a greater reversibility after 150 cycles, because the extended pores are beneficial to the oxygen diffusion. Overall, Ba 0.5 Sr 0.5 CoO 3-δ is suggested as a suitable TCES material with a reaction enthalpy of 202.20 kJ kg −1. This study provides a design principle of composite perovskites for thermochemical energy storage.