Bifunctional thermochemical energy storage and air separation performance of perovskite-type BaCoO3−δ oxygen carriers

The development of high-performance materials that integrate thermal energy storage and oxygen production is essential for advancing sustainable, low-carbon energy systems. BaCoO 3− δ (BCO) utilizes reversible redox reactions in air to enable chemical looping for simultaneous thermochemical heat storage and air separation. This process synergistically stores solar energy through combined sensible and thermochemical mechanisms, significantly enhancing thermal storage density in concentrated solar power (CSP) plants, thereby improving their efficiency and sustainability. Moreover, the lattice oxygen released during the reduction phase can be directly utilized for oxygen-enriched combustion integrated with supercritical   CO 2 power cycles, which reduces fossil fuel consumption and carbon emissions. Comprehensive thermodynamic and kinetic analysis of BCO powder synthesized via solid-state reaction revealed a reaction enthalpy of 171.8J/g, a total heat storage capacity of 383.21 J/g within 1073–1273 K, and an oxygen storage capacity of 1562.5 µmol-O/g. The redox kinetics followed shrinking-core reduction and second-order oxidation models, demonstrating exceptional cycling reversibility. To overcome powder mechanical limitations while preserving reaction characteristics, BCO ball-shaped granules and honeycomb porous foams were fabricated via single-step forming. Thermochemical cycling tests confirmed complete structural integrity and dimensional stability over 56 cycles between 973 and 1273 K in air, with no detectable degradation. These findings establish BCO-based materials as a transformative solution for high-efficiency, environmentally sustainable energy systems, effectively bridging solar energy utilization with clean combustion technology to support a greener energy infrastructure.