Three-dimensional hollow spheres of the tetragonal-spinel MgMn2O4 cathode for high-performance magnesium ion batteries

We report a simple and template-free method for preparing uniform tetragonal-spinel MgMn2O4 (T-MgMn2O4) hollow spheres, which self-assembled from small sized nanocrystals. The obtained T-MgMn2O4 hollow spheres with a micro/nanostructure exhibit excellent rate performance and long cycle life as the cathode for magnesium ion batteries.