Unravelling the growth mechanism of hierarchically structured Ni1/3Co1/3Mn1/3(OH)2 and their application as precursors for high-power cathode materials

Abstract A hydroxide co-precipitation method is used to synthesize transition metal hydroxide (Ni 1/3 Co 1/3 Mn 1/3 (OH) 2 ), which is the precursor for layer-structured LiNi 1/3 Co 1/3 Mn 1/3 O 2 . The optimum pH range for the preparation of Ni 1/3 Co 1/3 Mn 1/3 (OH) 2 using a continuous stirred-tank reactor is calculated by taking into account the underlying chemical equilibria. The entire growth process of the Ni 1/3 Co 1/3 Mn 1/3 (OH) 2 particles is investigated by monitoring the structure, morphology, particle size distribution, and tap density as a function of the reaction time. The results confirm that the co-precipitation reaction in the presence of ammonia started with the formation of crystal nuclei and (001) plane dominated nanosheets. The reaction ended with spherical and dense hydroxide precursors. The crystal growth mechanism was interpreted during the co-precipitation process, which involved the quick nucleation of primary particles followed by its slow aggregation and crystallization. The electrochemical properties of the final cathode materials with different morphologies are also studied. The results show that the electrochemical performances of the final LiNi 1/3 Co 1/3 Mn 1/3 O 2 are strongly affected by the hierarchical structure of Ni 1/3 Co 1/3 Mn 1/3 (OH) 2 .