Lithium-Rich Nanoscale Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ Cathode Material Prepared by Co-Precipitation Combined Freeze Drying (CP-FD) for Lithium-Ion Batteries

Nanoscale Li-rich Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ material is synthesized by a co-precipitation combined freeze drying (CP-FD) method, and compared with a conventional co-precipitation method combined vacuum drying (CP-VD). With the combination of X-ray diffraction (XRD) and scanning electron microscopy (SEM), it is found that the sample from CP-FD method consists of a pure phase with good crystallinity and small, homogenous particles (100-300nm) with uniform particle size distribution. Inductively coupled plasma spectroscopy (ICP) shows that the sample has a stoichiometric ratio of n_(Li):n_(Mn):n_(Ni):n_(Co)=9:4:1:1; and its Brunauer-Emmett-Teller (BET) specific surface area is 5.749m²g^-1. This sample achieves excellent electrochemical properties: its initial discharge capacities are 298.9mAhg^-1 at 0.1C (20mAg^-1), 246.1mAhg^-1 at 0.5C, 215.8mAhg^-1 at 1C, and 154.2mAhg^-1 at 5C (5C charge and 5C discharge), as well as good cycling performance. In addition, the Li⁺ chemical diffusion coefficient of Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ material prepared by the CP-FD method is 4.59×10^-11cm²s^-1, which is higher than that of the Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ material prepared by CP-VD. This phenomenon illustrates the potential for Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ with good rate performance synthesized by CP-FD method.