Three-dimensional hollow spheres of the tetragonal-spinel MgMn 2 O 4 cathode for high-performance magnesium ion batteries

Uniform tetragonal-spinel MgMn ₂ O ₄ (T-MgMn ₂ O ₄ ) hollow spheres with a micro/nanostructure are synthesized by using a simple and template-free method and they exhibit outstanding electrochemical performance as the cathode material for magnesium ion batteries.