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Selective TiO 2 Nanolayer Coating by Polydopamine Modification for Highly Stable Ni‐Rich Layered Oxides
Author(s) -
Kim Hyeongwoo,
Jang Jihye,
Byun Dongjin,
Kim HyungSeok,
Choi Wonchang
Publication year - 2019
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201902998
Subject(s) - materials science , coating , cathode , calcination , chemical engineering , surface modification , electrochemistry , degradation (telecommunications) , layer (electronics) , lithium (medication) , nanotechnology , catalysis , electrode , organic chemistry , chemistry , engineering , medicine , telecommunications , endocrinology , computer science
Ni‐rich layered oxides are promising cathode materials for developing high‐energy lithium‐ion batteries. To overcome the major challenge of surface degradation, a TiO 2 surface coating based on polydopamine (PDA) modification was investigated in this study. The PDA precoating layer had abundant OH catechol groups, which attracted Ti(OEt) 4 molecules in ethanol solvent and contributed towards obtaining a uniform TiO 2 nanolayer after calcination. Owing to the uniform coating of the TiO 2 nanolayer, TiO 2 ‐coated PDA‐LiNi 0.6 Co 0.2 Mn 0.2 O 2 (TiO 2 ‐PNCM) displayed an excellent electrochemical stability during cycling under high voltage (3.0–4.5 V vs. Li + /Li), during which the cathode material undergoes a highly oxidative charge process. In addition, TiO 2 ‐PNCM exhibited excellent cyclability at elevated temperature (60 °C) compared with the bare NCM. The surface degradation of the Ni‐rich cathode material, which is accelerated under harsh cycling conditions, was effectively suppressed after the formation of an ultra‐thin TiO 2 coating layer.