Directional and Orderly Arranged NiMn(OH) Enables the Synthesis of Single-Crystal Ni-Rich Co-Free LiNiMnO with Enhanced Internal Structural Stability.

In this paper, the effect of the structure characteristics of the precursor on the electrochemical properties of a single-crystal cobalt-free high-nickel LiNiMnO cathode is systematically studied. Precursors with different morphologies are synthesized by adjusting the coprecipitation reaction conditions. The results of SEM and XRD show that with the increase in the orderly stacking arrangement of internal primary nanosheets of NiMn(OH), the exposed active {010} planes at the surface increase. The prepared cathode materials finally inherit the structural features of the precursor, and the single-crystal Co-free Ni-rich LiNiMnO cathode with highly exposed active {010} planes shows a well-ordered crystal structure and low Li/Ni cation mixing. The characterization results reveal that the high percentage of {010} planes will improve the Li transportation kinetics, decrease electrochemical impedance, and significantly alleviate the accumulation of rock-salt phases. Therefore, the material with this structure shows good electrochemical performance.