Growth mechanisms for spherical Ni0.815Co0.15Al0.035(OH)2 precursors prepared via the ammonia complexation precipitation method

• 作者: Xi Yang Xuesong Huang Hancheng Shi Peng Dong Ding Wang Jianguo Duan Yingjie Zhang
• 来源期刊: 能源化学
• 年，卷（期）: 2021,（2）
• 页码范围: 379-386
• 页数: 8页
• 语种: 英文

摘要

The microstructures of precursors strongly affect the electrochemical performance of Ni-rich layerstructured cathode materials.In this study,the growth behaviour of Ni0.815Co0.15Al0.035(OH)2 (NCA) prepared via the ammonia complexation precipitation method in a 50-L-volume continuously stirred tank reactor (CSTR) is studied in detail.The growth of Ni(OH)2-based hydroxide can be divided into a nucleation process,an agglomeration growth process,a process in which multiple growth mechanisms coexist,and an interface growth process over time,while the inner structure of the CSTR can be divided into a nucleation zone,a complex dissolution zone,a growth zone,and a maturation zone.The concentration of ammonium ions affects the growth habit of the primary crystal significantly due to its specific adsorption on the electronegative crystal plane.When the ammonia concentration is ＜1.5 mol L-1 at 60 ℃ at pH =11.5,the precursors grow preferentially along the (1 0 1) crystal plane,whereas they grow preferentially along the (0 0 1) crystal plane when the concentration is ＞2.0 mol L-1.The LiNi0.815Co0.15Al0.035O2 materials inherit the grain structure of the precursor.Materials prepared from precursors with (1 0 1) preferential primary particles show a higher specific capacity and better rate performance than those that were prepared from (0 0 1) preferential primary particles,but the latter realize a better cycling performance than the former.