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Synergistic structure of LiFeO2 and Fe2O3 layers with electrostatic shielding effect to suppress surface lattice oxygen release of Ni-rich cathode
Chemical Engineering Journal ( IF 13.3 ) Pub Date : 2023-04-05 , DOI: 10.1016/j.cej.2023.142750
Youqi Chu , Yongbiao Mu , Lingfeng Zou , Jie Cheng , Shibo Xi , Qichang Pan , Meisheng Han , Hongqiang Wang , Qingyu Li , Fenghua Zheng , Qing Zhang , Lin Zeng

The Ni-rich cathodes used for lithium-ion batteries (LIBs) suffer from severe surface side reactions, slow kinetics, and microcracks during long-term cycling. To address these problems, a dual-modified protective coating consisting of LiFeO2&Fe2O3 layers (denoted as LFO) was fabricated on the surface of the cathode material LiNi0.8Co0.1Mn0.1O2 (NCM811) by capturing the lithium impurities in the electrolyte solution using an electric field. The LiFeO2 layer acts as an ionic conductor, accelerating interfacial Li+ transport, and exhibits a synergistic effect with the bulk material during the charging/discharging process. The Fe2O3 layer, which contains abundant oxygen vacancies, acts as an electrostatic shielding layer and effectively inhibits the outward migration of Oα− (α < 2), thus improving the structural stability. Hence, the interface-protected NCM@LFO3 cathode showed excellent cycling stability (capacity retention of 82.4% after 600 cycles at 1 C) and even at a high cut-off voltage of 4.5 V (capacity retention of 88.9 % after 200 cycles at 1 C).



中文翻译:

具有静电屏蔽作用的LiFeO2和Fe2O3层协同结构抑制富镍正极表面晶格氧释放

用于锂离子电池 (LIB) 的富镍阴极在长期循环过程中会出现严重的表面副反应、缓慢的动力学和微裂纹。为了解决这些问题,通过捕获锂杂质,在正极材料 LiNi 0.8 Co 0.1 Mn 0.1 O 2 ( NCM811) 表面制备了由 LiFeO 2 &Fe 2 O 3层组成的双改性保护涂层(表示为 LFO)在使用电场的电解质溶液中。LiFeO 2层充当离子导体,加速界面 Li +运输,并在充电/放电过程中与散装材料表现出协同效应。含有丰富氧空位的Fe 2 O 3层作为静电屏蔽层,有效抑制O α- (α < 2)的向外迁移,从而提高结构稳定性。因此,界面保护的 NCM@LFO3 正极表现出优异的循环稳定性(在 1 C 下循环 600 次后容量保持率为 82.4%),甚至在 4.5 V 的高截止电压下(在 1 C 下循环 200 次后容量保持率为 88.9%) C)。

更新日期:2023-04-05
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