Thermochemical Energy Storage Using Perovskite Oxides—A Review

ABSTRACT Thermochemical energy storage (TCES) based on reversible redox reactions of metal oxides has emerged as a promising solution for high‐temperature energy storage in next‐generation concentrating solar power (CSP) systems. Among the candidate materials, perovskite oxides (ABO 3‐ δ ) are particularly attractive due to their compositional tunability, ability to sustain continuous and reversible oxygen non‐stoichiometry, and structural stability under repeated high‐temperature redox cycling. These characteristics enable systematic optimization of redox thermodynamics, oxygen exchange capacity, and reaction kinetics for advanced CSP applications. Accordingly, this review critically assesses perovskite oxide–based TCES materials with emphasis on redox thermodynamic behavior, oxygen exchange characteristics, kinetic performance, and system‐level relevance. La‐, Ba‐, Sr‐, and Ca‐based perovskite families are systematically examined, highlighting the complementary roles of A‐site and B‐site substitution in controlling reduction temperature, oxygen vacancy energetics, redox extent, and cycling durability. Many cobalt‐ and iron‐containing perovskites exhibit high oxygen exchange capacities, with reversible oxygen non‐stoichiometry changes of Δ δ ≈ 0.25–0.50 and reduction onset temperatures as low as ~300°C–500°C, enabling rapid charging and discharging. In contrast, calcium manganite–based perovskites operate at higher temperatures (~700°C–1100°C) but demonstrate exceptional thermal robustness and high reduction enthalpies, achieving total TCES densities exceeding ~800–1000 kJ/kg through combined sensible and chemical storage. Experimental demonstrations in TGA systems, packed beds, fluidized beds, porous structures, and directly irradiated granular‐flow reactors confirm feasibility beyond idealized equilibrium conditions. The review further identifies key challenges related to kinetics, heat and mass transfer, and reactor‐scale integration, while outlining future opportunities for materials optimization and system‐level deployment.