Unveiling Morphology and Crystallinity Dynamics in Ni<sub><i>x</i></sub>Mn<sub>1–<i>x</i></sub>CO<sub>3</sub> Cathode Precursors through Batch-Mode Coprecipitation
Jiajun Chen, Arturo Gutierrez, Maksim Sultanov, Jianguo Wen, Jason R. Croy, Yan Wang, Venkat Srinivasan, Pallab Barai
Abstract
This study delves into the synthesis and control of Ni x Mn 1– x CO 3, a critical class of Mn-rich, Co-free precursors vital for cathode-oxide materials in energy storage and conversion technologies. Employing batch-mode coprecipitation, we systematically generated samples with varying Ni concentrations ( x = 0, 0.1, 0.3, 0.5, 0.7, and 0.9) and conducted a comprehensive analysis of their compositions, crystallinities, transition-metal distributions, and particle morphologies through both experimental and computational methods. A significant variation in particle size and crystallinity was observed, contingent on the Ni content. A pivotal transition emerged at Ni concentrations above x = ∼0.5, transforming uniform morphologies, such as spherical, monodisperse, pseudo-single-crystalline particles, into bimodal, polycrystalline structures. Furthermore, the study highlights the role of Ni–ammonia complexes leading to Ni-deficient precipitates and underscores the importance of ammonia concentration in achieving precise Ni content control. This study unveils critical reaction conditions governing Mn-rich precursor properties that are vital for cathode-oxides, emphasizing the need for meticulous synthetic control and offering the potential for practical applications in advanced energy storage and conversion systems.