Synthesis of Single-Crystal LiNi0.7Co0.15Mn0.15O2 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 LiNi 0.7Co0.15Mn0.15O2, the as-prepared single-crystal material exhibits improved thermal stability, less microcrack, and lower transitionmetal dissolution. As a result, the long-life performance is improved for both coin cells and Al-shell cells.