Selective TiO2 Nanolayer Coating by Polydopamine Modification for Highly Stable Ni-Rich Layered Oxides.,ChemSusChem

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Selective TiO2 Nanolayer Coating by Polydopamine Modification for Highly Stable Ni-Rich Layered Oxides.
ChemSusChem ( IF 7.5 ) Pub Date : 2019-11-12 , DOI: 10.1002/cssc.201902998
Hyeongwoo Kim _{1,

2} , Jihye Jang _{1,

3} , Dongjin Byun ₂ , Hyung-Seok Kim ₁ , Wonchang Choi ₄

Affiliation

Ni-rich layered oxides are promising cathode materials for developing high-energy lithium-ion batteries. To overcome the major challenge of surface degradation, a TiO2 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 TiO2 nanolayer after calcination. Owing to the uniform coating of the TiO2 nanolayer, TiO2 -coated PDA-LiNi0.6 Co0.2 Mn0.2 O2 (TiO2 -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, TiO2 -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 TiO2 coating layer.

中文翻译：

聚多巴胺改性的选择性 TiO2 纳米层涂层用于高度稳定的富镍层状氧化物。

富镍层状氧化物是开发高能锂离子电池的有前途的阴极材料。为了克服表面降解的主要挑战，本研究研究了基于聚多巴胺 (PDA) 改性的 TiO2 表面涂层。PDA 预涂层具有丰富的 OH 儿茶酚基团，在乙醇溶剂中吸引 Ti(OEt)4 分子，有助于在煅烧后获得均匀的 TiO2 纳米层。由于 TiO2 纳米层的均匀涂层，TiO2 涂层的 PDA-LiNi0.6 Co0.2 Mn0.2 O2 (TiO2 -PNCM) 在高电压循环期间表现出优异的电化学稳定性（3.0-4.5 V vs. Li+ /Li )，在此期间正极材料经历高度氧化充电过程。此外，与裸露的 NCM 相比，TiO2-PNCM 在高温 (60 °C) 下表现出出色的循环性能。

更新日期：2019-11-27

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