Investigation of the physical and electrochemical properties of LiLaxMn2-xO3.85F0.15 cathode materials

Lanthanum substituted spinel LiLaxMn2-xO3.85F0.15 (x = 0.01, 0.02, 0.03, 0.05) cathode materials were synthesized by solid-state reaction method using LiLaxMn2-xO4 oxides with (NH4)HF2 at low temperature (500 °C). Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area analyzer, Fourier transform infrared (FT-IR) spectroscopy and charge-discharge test were employed to investigate the physical and electrochemical properties of the synthesized samples. The obtained results revealed that the physical and electrochemical properties of all samples were significantly affected by La substitution. In the charge-discharge tests, the specific capacity of the spinel material with x = 0.01 was found to be 119.7 mAhg−1. For further increase of x values, the specific capacity of the samples decreased and reached about 73.7 mAhg−1 when x = 0.05. From the cyclability performance study, it was found that the spinel material with x = 0.02 exhibited capacity retention of 96.4% after fifteen cycles and it is a promising 4.5 V cathode material. However, for further increase of x values, the capacity retention performance of the samples decreased and reached about 81.5% for x = 0.05. •LiLaxMn2-xO3.85F0.15 cathodes are successfully synthesized.•All samples have mesoporous-macroporous structure.•The hysteresis loops belong to H3.•Small amount La substitution for Mn is effective in improving the electrochemical performance.•LiLa0.02Mn1.98O3.85F0.15 material exhibits superior capacity retention performance.