Microstructure and energy storage properties of Li1.2[Mn0.52-0.5xNi0.20-0.5xCo0.08+x]O2 cathode materials

The MCO₃ precursor was synthesized via co-precipitation using Na₂CO₃ and C₃H₅O₃Na as the precipitation and complexing agents, then the mixtures of MCO₃ precursor and LiOH·H₂O were calcined at 950℃ to form the Li_1.2Mn_0.52-0.5xNi_0.2-0.5xCo_0.08+x]O₂ (x=0, 0.02, 0.04, 0.06) series cathode materials. The influence of element content changes in Li_1.2Mn_0.52-0.5xNi_0.20-0.5xCo_0.08+x]O₂ on the microstructure and charge-discharge properties of Li_1.2Mn_0.52-0.5xNi_0.2-0.5xCo_0.08+x]O₂ cathode materials has been investigated. The results showed that the value of c/a for the lattice parameter is increased when the x value increases. When x is 0.02, the material showed the best properties with the initial discharge capacity of 261.0 mA·h/g, a capacity retention of 98.85% (189.9 mA·h/g ) after 100 cycles at 0.5 C and a discharge capacity of 157.6 mA·h/g at 2 C. With the further increase of x value (the rise of Co content), more 2g band of Co^3+/4+ overlapped with the 2p band of O^2- happens and it shows lower specific capacity and cycle ability.