Hydrothermal synthesis of MnCO3 nanorods and their thermal transformation into Mn2O3 and Mn3O4 nanorods with single crystalline structure

MnCO3 nanorods with diameters of 50–150 nm and lengths of about 1–2 μm have been prepared for the first time by a facile hydrothermal method. Mn2O3 and Mn3O4 nanorods were obtained via the heat-treatment of the MnCO3 nanorods in air and nitrogen atmosphere, respectively. The morphology and structure of the as-synthesized MnCO3, Mn2O3 and Mn3O4 nanorods were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction. It was found that the MnCO3 nanorods are single-crystalline, and their morphology and single-crystalline characteristic can be sustained after thermal transformation into Mn2O3 and Mn3O4. The corresponding growth directions for MnCO3, Mn2O3 and Mn3O4 nanorods were [2 1 4], [1 0 0] and [1 1 2], respectively. When applied as anode materials for lithium ion batteries, the Mn2O3 and Mn3O4 nanorods exhibited a reversible lithium storage capacity of 998 and 1050 mAh/g, respectively, in the first cycles.

► MnCO3 nanorods were synthesized for the first time by a facile and mild hydrothermal method, and Mn2O3 and Mn3O4 nanorods can be obtained via the heat-treatment of the MnCO3 nanorods under different conditions.
► It was revealed that the MnCO3 nanorods can sustain their morphology and single-crystalline characteristic after thermal transformation into Mn2O3 and Mn3O4.
► The Mn2O3 and Mn3O4 nanorods as anode materials for lithium ion batteries exhibited a reversible lithium storage capacity as high as 998 and 1050 mAh/g, respectively, in the first cycles.