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Enhanced Electrochemical Performance of Li‐ and Mn‐Rich Cathode Materials by Particle Blending and Surface Coating
Author(s) -
Li Zhao,
Li Qiang,
Wu Shuaijin,
Zhang Anbang,
Zhuo Haoxiang,
Zhang Gangning,
Wang Zhong,
Wang Lin,
Ren Zhimin,
Wang Jiantao
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201904290
Subject(s) - materials science , x ray photoelectron spectroscopy , coating , electrolyte , chemical engineering , electrochemistry , particle (ecology) , cathode , scanning electron microscope , calcination , transmission electron microscopy , nanoparticle , particle size , electrode , composite material , nanotechnology , chemistry , catalysis , oceanography , engineering , geology , biochemistry
A Li‐ and Mn‐rich material Li 1.18 Mn 0.55 Ni 0.18 Co 0.09 O 2 (LMR) exhibits a high specific capacity; however, this material has serious problems, including a poor rate capability and limited cycling life. A jet crushing method is used to break micron‐sized LMR particles synthesized by a solid‐state reaction into nano‐sized particles. Compared to micron‐sized particles, nano‐sized LMR particles possess a higher rate capability due to shorter Li + diffusion pathway, but also an increase in side reactions with the electrolyte leads to poorer cycling performance. Herein, we propose a material engineering strategy that combines micron‐ and nano‐sized particle blending and a cerium oxide (CeO 2 ) surface coating modifications to enhance the electrochemical performance of LMR material. X‐ray diffraction (XRD) patterns and transmission electron microscopy (TEM) images demonstrate that the cubic structure of CeO 2 is uniformly distributed on the surface of LMR, which is supposed to suppress the electrode/electrolyte side reactions by preventing electrode particles from being directly exposed to the electrolyte. As a result, the discharge capacity of the modified LMR material is 153.1 mAh g −1 at 5 C compared to 139.1 mAh g −1 with the pristine material. The capacity retention of the modified material is 82.8 % after 200 cycles at 1 C, which is higher than the 77.1 % capacity retention of the pristine material. X‐ray photoelectron spectroscopy (XPS) reveals that the CeO 2 coating layer has a significant role in mitigating oxygen release from the surface of the LMR material during cycling.