Study the Effect of Different Temperatures on Structural and Morphological Features of Co-Doped LiMnO4

The spinel compound of LiCo 0.5Mn1.5O4 (LCMO) was synthesized as cathode active material for lithium–ion batteries by using sol–gel technique in this study. The substance was subjected to a thermo-gravimetric (TGA) study. The sample was calcined in the air for 12 hours at 700, 850, and 1000 ᵒC to examine differences in structural and morphological features. The thermogravimetry (DTG) curve of sample was fabricated at 850 °C. A loss region took place before 400 °C related to the evaporation regarding the adsorbed water molecules and the elimination of oxygen-containing functional groups. The powder crystallized in the phase structure space group Fd⋽m and has a random orientation, according to the XRD measurement. The LCMO powder's surface morphology comprises nano-grains crystallite with a homogeneous coverage of the sample surface and randomly oriented grains. LiCo0.5Mn1.5O4 synthesized at 850°C was taken after one charge/discharge cycle. The interfacial layer resistance, or Rf, is attributed to the impedance of Li+ ion migration through SEI film. From the EIS measurements, the diameter of the semicircle equal to charge transfer resistance, which is approximately 700 Ω. The capacity of the charging and discharging were of 121 mAhg-1 and 122 mAhg-1 delivered by the LiCo 0.5Mn1.5O4 cathode. Likewise, a columbic efficiency of 94% was obtained for the cathode.