Behavior of LiMn_2O_4 Single Crystals as Battery Cathodes

摘要

This paper deals with: ⅰ) the growth of LiMn_2O_4 crystals by electrocrystallisation; ⅱ) the response of these crystals in lithium cells; and ⅲ) a method to follow their structural and morphological changes while working as electrodes. The defects present in LiMn_2O_4 crystals are determined after refining the occupation at every site of the spinel structure by single-crystal X-ray diffraction analyses, which lead to define two possible paths for the process of Li deinsertion-insertion. It is shown how the crystals studied follow one of these paths during cycling of the battery by virtue of a dynamic mechanism consisting in Mn migrations cooperatively induced by Li insertion and extraction.