Synthesis of mesoporous Li–Mn spinel without post-template treatment

The ordered mesoporous Li–Mn spinels are of interest as the cathode material of Li-ion batteries and recently have been prepared by two steps of the templated synthesis of MnO2 or Mn2O3 and the post-template treatment to incorporate lithium ion. Here we show the synthesis of the Li–Mn spinel directly in the template without post-template treatment. SBA-15 (2d-hexagonal p6mm) or KIT-6 (bicontinuous cubic Ia3d) was used as the template. Li and Mn nitrates were infiltrated simultaneously into the mesoporous silica, and the assembly was calcined in air at temperatures between 500 and 700 °C. The structures and properties of the resultant materials were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and nitrogen adsorption desorption measurements. Calcined at 600 °C at the optimized preparation condition in which KIT-6 was used, the ordered mesoporous Li–Mn spinels showed high crystallinity with a high specific surface area of 160 m2 g−1, a discharge capacity of about 100 mA h g−1 at 0.1 C, and 76% of the reversible capacity at 0.1 C was retained at 10 C.

Transmission electron microscopy (TEM) images show that Li–Mn spinel replica from SBA-15 (a) is composed of nanowire bundle and that from KIT-6 (b) has 3-dimensional mesoporous structure.Figure optionsDownload as PowerPoint slideHighlights
► Mesoporous Li–Mn spinel (LMO) replicas are prepared without post-template treatment.
► Ordered mesoporous silicas (KIT-6 and SBA-15) are used as a template.
► Highly crystalline mesoporous LMO with good electrochemical properties are obtained.
► 3-dimensional cubic arrangement of pores of KIT-6 gives more stable mesoporous LMO.