Abstract
Calcination is a solid-state synthesis process extensively employed in the industrial manufacturing of cathode materials for batteries. However, achieving predictive control of the process to synthesize high-performance cathodes faces complexities associated with the formation of kinetic intermediates that are often elusive and tend to structurally and chemically evolve towards equilibrium phases.Herein, we use a combination of correlated in situ synchrotron X-ray diffraction (XRD), X-ray absorption spectroscopy (XAFS) and multiscale modeling to investigate the synthesis of the archetypical nickel-based cathode LiNiO2 via calcination from hydroxides. A multistage non-equilibrium crystallization of intermediates is uncovered, with the process dynamically driven by lithiation. Specifically, Li-intercalation occurs concomitantly with dehydration, resulting in the early emergence of Li-containing layered and rocksalt motifs upon the decomposition of Ni(OH)2 precursor. During the subsequent phase progression, crystal growth of the layered LiNiO2 goes slowly due to lithiation-limited sluggish mass transport, then abruptly accelerates upon full lithiation, while experiencing Li/O loss and structural degradation. These findings have immediate implications for the synthetic optimization of Ni-based cathodes, offering opportunities to tune their structural properties through lithiation control intentionally[1]. Figure 1. shows XRD and XAFS data of nickel hydroxide calcined at different temperature with and without Li source (LiOH.H2O).Reference:[1] A. Tayal et al. Adv. Mater. 2024, 2312027 Figure 1
Published Version
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