Experimental Investigation of Co–Cu, Mn–Co, and Mn–Cu Redox Materials Applied to Solar Thermochemical Energy Storage

Abstract

Thermochemical energy storage (TCES) can be achieved via reversible redox reactions based on metal oxides for solar energy storage applications in solar power plants. As cobalt oxide (Co3O4/CoO) and manganese oxide (Mn2O3/Mn3O4) appear as attractive candidates for TCES, an experimental study has been conducted to evaluate the potential of mixed oxides from the Co–Cu–O, Mn–Co–O, and Mn–Cu–O systems. The addition of Cu to Co3O4 allows accessing promising materials with good cycling stability and high reaction enthalpy for TCES applications. As for the Mn–Co–O and Mn–Cu–O systems, the role of the hausmannite phase formation at low Co or Cu contents on the irreversibility of Mn-based mixed oxides is made evident, thus demonstrating the interest of the addition of a secondary metal oxide to the Mn-based material. For the Mn–Co–O system, low amounts of Mn should be favored, since both the oxygen storage capacity and the reaction enthalpy significantly increase with decreasing Mn contents, and the reversibility ...