Exposing microstructure evolution of Ni-Rich Ni-Co-Al hydroxide precursor

Abstract Preparing excellent hydroxide precursor is a significant step in the synthesis of high-energy–density Ni-Rich cathode materials. Efforts to address their limited cycle life have focused on the structure of the precursor. Herein, we showed a systematic survey to reveal the structural evolution of Ni-Rich Ni-Co-Al hydroxide precursor under different synthesis conditions. Under a certain pH, the higher the ammonia concentration is, the larger the primary particle size gradually becomes. Simultaneously, at the low pH (pH = 11.2), Ni-Rich Ni-Co-Al hydroxide precursor is consisted of four phases: Ni(OH)2, AlO(OH), Al(OH)3 and Al2(SO4)3 with the space group P-3 m1, Cmcm, P21/n and R-3, respectively. At the harsh pH (pH = 11.8), the precursor is consisted of two phases: Ni(OH)2, and Al(OH)3 with the space group P-3 m1 and P21/n, respectively. This study provided a significant guidance for the design of the precursor with special structure.