Influence of Co increment on the electrochemical properties of Li1.2[Mn0.52−0.5xNi0.2−0.5xCo0.08+x]O2 cathode materials for lithium-ion batteries

• The environment friendly C3H5NaO3 is acted as complexing agent to replace NH3⋅H2O.
• MCO3 precursor is synthesized via using co-precipitation method.
• Mixtures of MCO3 and LiOH⋅H2O are calcined to form cathodes with various Co contents.
• Lattice parameters c/a ratio for cathode material increases with the Co increment increasing.
• Li1.2[Mn0.51Ni0.19Co0.1]O2 cathode shows the best electrochemical properties.

MCO3 precursors are synthesized via co-precipitation method using NaCO3 as the precipitation, and the environment friendly C3H5NaO3 is acted as complexing agent to replace NH3⋅H2O. And then the mixtures of MCO3 precursors and LiOH⋅H2O are calcined at 950 °C to form Li1.2[Mn0.52−0.5xNi0.2−0.5xCo0.08+x]O2 cathode materials with different Co increments. The influence of Co increment on the microstructure and electrochemical properties of Li1.2[Mn0.52−0.5xNi0.2−0.5xCo0.08+x]O2 cathode materials has been analyzed. The results show that the c/a ratio for cathode material becomes higher, and then the layered structure becomes better when the Co increment increases. Among them, Li1.2[Mn0.51Ni0.19Co0.1]O2 (x = 0.02) shows the best electrochemical properties with the initial discharge capacity of 261.0 mA h g−1, capacity retention of 99.4% (189.9 mA h g−1) after 100 cycles at the charging and discharging current density of 100 mA g−1 and highest discharge capacity of 157.6 mA h g−1 at the discharging current density of 400 mA g−1.