CaCo_0.05Mn_0.95O_3−δ: A Promising Perovskite Solid Solution for Solar Thermochemical Energy Storage

Abstract

The redox cycle of doped CaMnO3−δ has emerged as an attractive way for cost-effective thermochemical energy storage (TCES) at high temperatures in concentrating solar power. The role of dopants is mainly to improve the thermal stability of CaMnO3−δ at high temperatures and the overall TCES density of the material. Herein, Co-doped CaMnO3−δ (CaCo x Mn1–x O3−δ, x = 0–0.5) perovskites have been proposed as a promising candidate for TCES materials for the first time. The phase compositions, redox capacities, TCES densities, reaction rates, and redox chemistry of the samples have been explored via experimental analysis and theoretical calculations. The results demonstrate that CaCo0.05Mn0.95O3−δ showed an enhanced redox capacity (1000 °C at pO2 = 10–5 bar) without decomposition and provided the highest TCES density of ∼571 kJ kg–1 reported so far. The effective Co doping tended to increase the valence states of B-site cations in perovskite and facilitate the diffusion of the lattice oxygen atoms into the surface-active oxygen sites. Furthermore, the high cooling rates deteriorated the microstructure of CaCo0.05Mn0.95O3−δ particles and resulted in incomplete heat release, which is instructive to the design and operation of the TCES systems.

A review on high‐temperature thermochemical heat storage: Particle reactors and materials based on solid–gas reactions

“…Thermochemical redox cycle behavior of Ba and Sr series perovskites, doped calcium manganites and strontium-doped calcium manganites were investigated as well for advanced high-temperature TES (Carrillo et al, 2019). Recently, La x Sr 1Àx (Mn, Fe, Co)O 3Àδ , and Ba y Sr 1Ày F I G U R E 6 Volumetric and mass energy storage density for various reversible reactions CoO 3Àδ and CaCo 0.05 Mn 0.95 O 3Àδ perovskite oxide powders were investigated as potential TES materials Jin et al, 2021) to operate at high temperatures above 600 C. Darwish et al (2021) investigated the effect of Mn and Cu substitution on the SrFeO 3 perovskite for potential TES applications.…”

Perovskite Oxides for Energy Applications

“…Babiniec et al [31] have studied Al and Ti-doped CaMnO 3-δ which were showing lower specific energy capacity of 390 kJ kg -1 at temperatures above 1000 °C. The newest research conducted by Jin et al [32] investigated the application of CaCo 0.05 Mn 0.95 O 3−δ in the TCES systems. The results have shown an energy capacity of about 424 kJ kg -1 without losing reversibility.…”

Coupling of the water-splitting mechanism and doping-mixture method to design a novel Cr-perovskite for rapid and efficient solar thermochemical H2 production

“…The doping of cations [28][29][30][31][32] and mixture of oxides 33 can effectively modify perovskite materials for promising H 2 production capacity. To improve the STWS performance, we considered Fe/Zr cation doping and a ceria mixture in the Cr-perovskite materials.…”