Structural and electrochemical properties of aluminium doped LiMn2O4 cathode materials for Li battery: experimental and ab initio calculations

Abstract

Pristine and Al-doped lithium manganese oxide (LiAlxMn2-xO4) spinel cathode materials were successfully synthesized by combustion method using urea as reducer and fuel. The structural and electrochemical properties of the as-synthesized powders were characterized using scanning electron microscopy, x-ray diffraction, energy dispersive spectroscopy and charge/discharge testing. The effect of aluminium doping on the discharge capacity was studied for different aluminium concentration x= 0, 0.05, 0.1 and 0.5. The as-synthesized Al doped samples LiAl0.05Mn1.95O4 and LiAl0.1Mn1.9O4 exhibited higher discharge capacity for the first two cycles compared to the first cycle discharge capacity of pristine LiMn2O4. The first-principles calculations predict an increase in lattice parameter for x=0.05 and 0.1 to be responsible for the increase in first cycle discharge capacity for x=0.05 and 0.1. In addition, we have found that LiAl0.5Mn1.5O4 sample exhibited the more stable capacity than the other samples.