Facile synthesis of porous Mn2O3 hierarchical microspheres for lithium battery anode with improved lithium storage properties

Abstract

Mn2O3 microspheres assembled from porous nanosheets are successfully synthesized by a two-step method. First, a solvothermal treatment is employed to prepare the Mn–EG (EG = ethylene glycol) precursor consisting of hierarchical microspheres assembled with nanosheets using Mn(CH3COOH)2 as the reactant, and then Mn2O3 microspheres assembled with porous nanosheets are obtained by annealing the precursor powder in air at 600 °C for 3 h. The products are characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM). Based on experimental results, a possible formation mechanism is proposed. Most importantly, when evaluate as electrode materials for lithium-ion battery anode, the Mn2O3 porous hierarchical microspheres display reversible capacity as high as 748 mA h g−1 at 50 mA g−1 over 45 cycles, good cycling stability and rate capability, superior to that of most reported Mn2O3 material. The improved electrochemical performance may be attributed to the porous structure and relatively large surface area, which may reduce diffusion length for Li-ions and enhance structural integrity for buffering the volume variation during the redox reaction. Moreover, hierarchical structure with spherical morphology could reduce agglomeration during electrochemical cycling, which will result in the long cycling stability. These results suggest that the capacity of materials with poor lithiation activity could be improved by designing their porous hierarchical structure.