Mn₃O₄ Nanocrystals: Facile Synthesis, Controlled Assembly, and Application

We report a facile process for the controllable synthesis of the Mn₃O₄ nanocrystals with different sizes and shapes, which includes dots, rods, and wires in the presence of the surfactants dodecanol and oleylamine. It is notable that the uniform-sized nanocrystals were achieved under mild experimental conditions and the common inorganic salt, such as manganese(II) nitrate, was adopted as the precursor. Furthermore, the as-prepared monodisperse nanocrystals, as ideal building blocks, can be rationally assembled into three-dimensional (3D) Mn₃O₄ colloidal spheres, using a facile ultrasonication strategy. In particular, the 3D colloidal spheres can be successfully converted to LiMn₂O₄ nanocrystals, which show distinct electrochemical performance, mainly depending on their crystallinity and size.