Synthesis of Single-Crystal LiNi_0.7Co_0.15Mn_0.15O₂ Materials for Li-Ion Batteries by a Sol–Gel Method

Single-crystal cathode with a submicron particle size exhibits better cyclic stability and safety than their polycrystalline counterparts. However, high-temperature sintering, tedious steps, and unexpected product greatly hinder its industrial applications. Herein, we proposed to prepare single-crystal LiNi0.7Co0.15Mn0.15O2 by a sol–gel method, which can achieve uniform mixing at the molecular level. Besides, particle agglomeration almost does not occur for the products obtained at 890 °C, so the synthesis route does not require any crushing or molten-salt addition process. Single-crystal cathode particles have a diameter of about 1 μm. Compared with the conventional polycrystalline LiNi0.7Co0.15Mn0.15O2, the as-prepared single-crystal material exhibits improved thermal stability, less microcrack, and lower transition-metal dissolution. As a result, the long-life performance is improved for both coin cells and Al-shell cells.