Mechanochemical Synthesis and Electrochemical Properties of LiMn₂O₄

Spinel LiMn₂O₄ as a cathode material for lithium secondary batteries has been synthesized by a mechanochemical process, and its electrochemical properties have been characterized. Highly disordered nanocrystalline LiMn₂O₄ powders have been prepared by the mechanochemical processing of Li₂O and MnO₂ powder mixtures for 24 h. Electrochemical characterization of mechanochemically processed powder has shown that the intercalation of Li⁺ takes place with an initial capacity of 167 mA·h/g in the 2.5-4.3 V range and has better capacity retention as compared to the well-ordered crystalline LiMn₂O₄ powders. The better capacity retention of the mechanochemically processed LiMn₂O₄ powder may be attributed to the highly disordered structure that could accommodate the Jahn-Teller distortion of the spinel structure during Li⁺ intercalation around the 3 V region.