Abstract

The LiMn_2 − yAl_yO₄ spinel phases have been synthesised by wet-chemistry techniques using a methanolic solution of the metal acetates and dicarboxylic acid as a complexing agent. The formation temperature of LiMn_2 − yAl_yO₄ powders has been found to be as low as 350 °C using the succinic acid method. The physical properties of the synthesised products have been investigated by X-ray diffraction, Raman spectroscopy, thermal analyses, and electrical conductivity. To improve the rechargeable capacity of Li//LiMn₂O₄ cells, the electrochemical performances of LiMn_2 − yAl_yO₄ compounds as positive electrodes have been evaluated. The structural properties of the materials are very similar to LiMn₂O₄, the electrochemical performances show that the capacity is maintained at 95% of the initial value at the 50th cycle, this being explained by the change of the Mn³⁺/Mn⁴⁺ ratio in doped phases.