1. Understanding the Formation of the Truncated Morphology of High-Voltage Spinel LiNi0.5Mn1.5O4 via Direct Atomic-Level Structural Observations
- Author
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Xuejie Huang, Y. Chen, Hailong Yu, Liubin Ben, Wenwu Zhao, Bin Chen, and Hua Zhang
- Subjects
Morphology (linguistics) ,Materials science ,General Chemical Engineering ,Electron energy loss spectroscopy ,Spinel ,02 engineering and technology ,General Chemistry ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Focused ion beam ,0104 chemical sciences ,Ion ,Crystal ,Crystallography ,Octahedron ,Scanning transmission electron microscopy ,Materials Chemistry ,engineering ,0210 nano-technology - Abstract
High-voltage spinel LiNi0.5Mn1.5O4 cathode materials typically exhibit a perfect octahedral morphology; i.e., only the {111} planes are observed. However, a truncated octahedral morphology is sometimes observed with the appearance of both the {100} planes and the {111} planes. The underlying mechanism of this morphological transformation is unclear. CS corrected scanning transmission electron microscopy (STEM) techniques were used to study LiNi0.5Mn1.5O4 samples lifted by a focused ion beam (FIB) to determine the atomic-level crystal and electronic structures of the octahedral and truncated octahedral morphologies. STEM images directly show that the appearance of the {100} planes in the truncated octahedral particles of LiNi0.5Mn1.5O4 is closely associated with the atomic-level migration of Ni and Mn ions in the surface region. The STEM electron energy loss spectroscopy (EELS) confirms the presence of oxygen-deficient and Ni-rich areas, particularly in the region close to the newly formed {100} planes. Th...
- Published
- 2018