Electrochemical Properties of Spherical, Porous LiMn2−xMgxO4 Powders Prepared by Ultrasonic Spray Pyrolysis

Spherical LiMn2−xMgxO4 powders were prepared by the ultrasonic spray pyrolysis. As-prepared particles had a porous microstructure and were nonagglomerated, which had an average diameter of about 1 µm with narrow size distribution. XRD showed that as-prepared powders were well crystallized to spinel structure with Fd3m space group. ICP analysis revealed that Mg ions were homogeneously doped to LiMn2O4. As-prepared powders were used as cathode active material for lithium secondary battery and its electrochemical properties were investigated between 3.5 and 4.3 V. The first charge/discharge capacity of LiMn2O4 was 145 and 141 mAh g−1 at 0.1 mA cm−2, respectively. The discharge capacity of LiMn2O4 decreased with increasing cycle number. The first charge/discharge capacity of LiMn2−xMgxO4 was less than that of LiMn2O4. However, the cycle performance of LiMn2−xMgxO4 was superior to that of LiMn2O4.