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Cooling Induced Surface Reconstruction during Synthesis of High‐Ni Layered Oxides
Author(s) -
Zhang MingJian,
Hu Xiaobing,
Li Maofan,
Duan Yandong,
Yang Luyi,
Yin Chong,
Ge Mingyuan,
Xiao Xianghui,
Lee WahKeat,
Ko Jun Young Peter,
Amine Khalil,
Chen Zonghai,
Zhu Yimei,
Dooryhee Eric,
Bai Jianming,
Pan Feng,
Wang Feng
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201901915
Subject(s) - materials science , quenching (fluorescence) , cathode , transition metal , lithium (medication) , surface reconstruction , chemical engineering , surface (topology) , nanotechnology , chemistry , catalysis , optics , organic chemistry , medicine , physics , geometry , mathematics , engineering , fluorescence , endocrinology
Transition metal layered oxides have been the dominant cathodes in lithium‐ion batteries, and among them, high‐Ni ones (LiNi x Mn y Co z O 2 ; x ≥ 0.7) with greatly boosted capacity and reduced cost are of particular interest for large‐scale applications. The high Ni loading, on the other hand, raises the critical issues of surface instability and poor rate performance. The rational design of synthesis leading to layered LiNi 0.7 Mn 0.15 Co 0.15 O 2 with greatly enhanced rate capability is demonstrated, by implementing a quenching process alternative to the general slow cooling. In situ synchrotron X‐ray diffraction, coupled with surface analysis, is applied to studies of the synthesis process, revealing cooling‐induced surface reconstruction involving Li 2 CO 3 accumulation, formation of a Li‐deficient layer and Ni reduction at the particle surface. The reconstruction process occurs predominantly at high temperatures (above 350 °C) and is highly cooling‐rate dependent, implying that surface reconstruction can be suppressed through synthetic control, i.e., quenching to improve the surface stability and rate performance of the synthesized materials. These findings may provide guidance to rational synthesis of high‐Ni cathode materials.