Effect of lithium content on electrochemical property of Li1+x(Mn0.6Ni0.2Co0.2)1-xO2 (0≤x≤0.3) composite cathode materials for rechargeable lithium-ion batteries

Abstract In order to confirm the optimal Li content of Li-rich Mn-based cathode materials (a fixed mole ratio of Mn to Ni to Co is 0.6:0.2:0.2), Li 1+ x (Mn 0.6 Ni 0.2 Co 0.2 ) 1- x O 2 ( x =0, 0.1, 0.2, 0.3) composites were obtained, which had a typical layered structure with and C 2/ m space group observed from X-ray powder diffraction (XRD). Electron microscopy micrograph (SEM) reveals that the particle sizes in the range of 0.4-1.1 μm increase with an increase of x value. Li 1.2 (Mn 0.6 Ni 0.2 Co 0.2 ) 0.8 O 2 sample delivers a larger initial discharge capacity of 275.7 mA·h/g at the current density of 20 mA/g in the potential range of 2.0–4.8 V, while Li 1.1 (Mn 0.6 Ni 0.2 Co 0.2 ) 0.9 O 2 shows a better cycle performance with a capacity retention of 93.8% at 0.2 C after 50 cycles, showing better reaction kinetics of lithium ion insertion and extraction.