Metal oxides for thermochemical energy storage: A comparison of several metal oxide systems

Among pure metal oxides only cobalt oxide, iron oxide, copper oxide and manganese oxide show suitable reaction temperatures, reaction enthalpies, cycling stabilities and material costs. To broaden the range of suitable metal oxides binary oxide systems were analyzed in the present study. In the following several compositions of eight binary metal oxide systems as well as the listed pure metal oxides were tested in terms of their ability to store energy thermochemically. Cobalt oxide/iron oxide, copper oxide/cobalt oxide, copper oxide/manganese oxide and manganese oxide/iron oxide are found to show high potential as thermochemical storage material. It was shown, however, that none of the tested systems fulfill all the requirements of an ideal storage material regarding storage capacity, costs and cycling stability.