High-Shear co-Precipitation synthesis of high-performance LiNi0.6Co0.198Mn0.2La0.002O2 materials

First, UV stopped-flow profiles were measured upon rapid mixing a series of soluble metal salt precursors with the Na2CO3 solution to detect the kinetics of the complicated process involving the insoluble material formation reaction and the subsequent nanoparticles growth. Comparing the kinetic curves in 60 ms with 300 ms at 45~65oC, it illustrates that the formation reaction of insoluble transition metal carbonates occurs rapidly (shorter than 60 ms) and precipitates as nanoparticles that act as the seeds for the subsequent particle growth. Then, a High-Shear co-Precipitation (HSP) method was developed to synthesize uniform LiNi0.6Co0.2-xMn0.2LaxO2, overcoming the inherent difference of tens of magnitude in the solubility product constant (Ksp) of individual carbonates. The synthesized LiNi0.6Co0.198Mn0.2La0.002O2 exhibits an initial discharge capacity of 200.5 mAh·g-1, superior to LiNi0.6Co0.2Mn0.2O2 (194.7 mAh·g-1, 0.1C). In addition, the phosphorous coating of LiNi0.6Co0.198Mn0.2La0.002O2 increased the capacity retention up to 86.4% (400th, 5C). DFT calculations indicate that La-intercalation can enlarge the Li+ layer spacing and reduce the Li+ migration energy barrier. This work illustrates the importance of the pulverization effects exerted by the High-Shear force on various insoluble nanoparticles during the initial rapid mixing period, providing a useful tool for manufacturing heteroatom-intercalated bulk nickel-rich cathode material.