Cathodes for Mg batteries: a condensed review

Magnesium batteries offer several advantages over commercial lithium batteries, including predicted lower cost due to the greater abundance of Mg, and better theoretical performance. Currently, there are numerous challenges to overcome in delivering commercial Mg batteries, such as the high charge density of Mg2＋ that hinders its intercalation in and out the cathode, or strict requirements for coordination of Mg2＋. In this condensed review, we present an overview of some of the key challenges and strategies for high performance, focusing on the cathode. We highlight some promising cathode compositions, including manganese oxides, the seminal Mo6S8 that is still used to evaluate novel electrolytes and anodes, and vanadium oxides, such as H2V3O8. Correlations between structure, chemistry and performance are discussed for each composition.