Magnifying Opportunities in Mg Batteries through Metastability

In the March issue of Chem, Andrews, Banerjee, and colleagues devise a clever strategy to synthesize a metastable one-dimensional polymorph of V2O5 and demonstrate reversible chemical and electrochemical Mg intercalation, with 90 mAh/g capacity retained after 50 cycles at an average cell potential of 1.65 V versus Mg metal. Their approach proves fruitful not only in identifying a new functional multivalent cathode material, but also in validating a general concept that metastable compounds can offer sufficiently low migration energies to support reversible cycling with multivalent ions.