Understanding the Origin of Li2MnO3 Activation in Li‐Rich Cathode Materials for Lithium‐Ion Batteries |
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Authors: | Delai Ye Guang Zeng Kazuhiro Nogita Kiyoshi Ozawa Marlies Hankel Debra J Searles Lianzhou Wang |
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Affiliation: | 1. Nanomaterials Centre, School of Chemical Engineering and Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia;2. Nihon Superior Centre for the Manufacture of Electronic Materials (NS CMEM), School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD, Australia;3. National Institute for Materials Science, Tsukuba, Ibaraki, Japan;4. AIBN Centre for Theoretical and Computational Molecular Science, The University of Queensland, Brisbane, QLD, Australia;5. School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia |
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Abstract: | Li‐rich layered cathode materials have been considered as a family of promising high‐energy density cathode materials for next generation lithium‐ion batteries (LIBs). However, although activation of the Li2MnO3 phase is known to play an essential role in providing superior capacity, the mechanism of activation of the Li2MnO3 phase in Li‐rich cathode materials is still not fully understood. In this work, an interesting Li‐rich cathode material Li1.87Mn0.94Ni0.19O3 is reported where the Li2MnO3 phase activation process can be effectively controlled due to the relatively low level of Ni doping. Such a unique feature offers the possibility of investigating the detailed activation mechanism by examining the intermediate states and phases of the Li2MnO3 during the controlled activation process. Combining powerful synchrotron in situ X‐ray diffraction analysis and observations using advanced scanning transmission electron microscopy equipped with a high angle annular dark field detector, it has been revealed that the subreaction of O2 generation may feature a much faster kinetics than the transition metal diffusion during the Li2MnO3 activation process, indicating that the latter plays a crucial role in determining the Li2MnO3 activation rate and leading to the unusual stepwise capacity increase over charging cycles. |
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Keywords: | high energy density batteries in situ characterization Li‐rich cathode materials phase activation reaction kinetics |
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