Lithium-rich cathode materials have become one of the most promising cathode materials for high-energy-density lithium-ion batteries. However, the electrochemical properties of lithium-rich cathode materials are highly sensitive to the local structure in the bulk and at the surface, which is closely associated with the synthesis process. In the present work, we provided new insights into the structural properties and corresponding electrochemical performance of Li1. 2xMn0. 54Ni0. 13Co0. 13O2 materials as a function of x (Li content) from a synthesis point of view. The spinel and Li2CO3 species in the bulk and at the surface arising from the varying amounts of lithium ions would result in the local compositional change within the as-prepared particles and provoke a change in the voltage-capacity profile as determined by electrochemical analysis, XRD, Raman, and XPS observations. Our results revealed that the as-prepared sample with 5% excess of Li in molar ratio utilized for the material synthesis showed better electrochemical performance in terms of discharge capacity ( ~270 mAh/ g) and voltage in comparison to other as-prepared samples with different Li contents.