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 degrees 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 mu m. Compared with the conventional polycrystalline LiNi0.7Co0.15Mn0.15O2, 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.