通过Ni梯度浓度自形成的尖晶石层原子尺度界面积分抑制富Ni LiNi 0.8 Co 0.1 Mn 0.1 O 2的结构劣化,ACS Applied Materials & Interfaces

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通过Ni梯度浓度自形成的尖晶石层原子尺度界面积分抑制富Ni LiNi _0.8 Co _0.1 Mn _0.1 O ₂的结构劣化
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2017-08-24 00:00:00 , DOI: 10.1021/acsami.7b08802
Jicheng Zhang ₁ , Zhenzhong Yang ₂ , Rui Gao ₁ , Lin Gu ₂ , Zhongbo Hu ₁ , Xiangfeng Liu ₁

Affiliation

富镍的层状阴极由于其高的比容量而引起了人们的极大兴趣，但是它们遭受了层状结构劣化以及由此导致的差的循环性和较差的储存性能的困扰。本文中，我们提出了一种新颖的简便策略，以在层状LiNi _0.8 Co _0.1 Mn _0.1 O ₂的表面上原位生成集成的尖晶石层。（SC-LNCMO）通过pH调节引起前体中Mn离子价数的梯度变化。通过这种策略，自形成的尖晶石层通过原子尺度的界面结紧密地集成到分层相中，并且还形成了从外到内的Ni梯度浓度，这增强了界面键合，减少了表面层-主体相失配，减轻了Li ⁺ / Ni ^2+的混合，并显着增强了LiNi _0.8 Co _0.1 Mn _0.1 O ₂的结构稳定性在充放电循环中。这些有助于大大提高循环稳定性，速率能力和低温性能。更重要的是，由于有效地抑制了集成尖晶石层对Ni ³⁺还原为Ni ²⁺，阳离子迁移和Li ⁺ / Ni ²⁺交换的有效抑制，SC-LNCMO的长期存储稳定性也得到了显着改善。和Li ₂ CO ₃编队。这项研究不仅为创建紧密集成的尖晶石层高性能阴极材料提供了一种简便的新策略，而且还提供了一些新见解，可以了解在充放电循环或长周期放电过程中富镍层状阴极材料的结构劣化和稳定机理。长期存储。

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Suppressing the Structure Deterioration of Ni-Rich LiNi0.8Co0.1Mn0.1O2 through Atom-Scale Interfacial Integration of Self-Forming Hierarchical Spinel Layer with Ni Gradient Concentration

Ni-rich layered cathodes have attracted great interest due to the high specific capacity, but they suffer from the layered structure deterioration and the resultant poor cyclability and inferior storage performance. Herein, we propose a novel facile strategy to in situ generate an integrated hierarchical spinel layer on the surface of layered LiNi_0.8Co_0.1Mn_0.1O₂ (SC-LNCMO) through a pH modulation induced gradient change of Mn ions valence in the precursor. The self-forming hierarchical spinel layer through this strategy is tightly integrated into the layered phase by atom-scale interfacial junctions, and a Ni gradient concentration from the outer to inner has also formed, which strengthens the interface bonding, reduces the surface layer–host phase mismatch, alleviates the Li⁺/Ni²⁺ mixing, and substantially enhances the structure stability of LiNi_0.8Co_0.1Mn_0.1O₂ during charge–discharge cycles. These contribute to the large improvement of the cycling stability, rate capability, and low-temperature performances. More importantly, the long-term storage stability of SC-LNCMO has also been significantly improved due to the effective suppression of the integrated spinel layer on the reduction of Ni³⁺ to Ni²⁺, cations migration and Li⁺/Ni²⁺ exchange, and Li₂CO₃ formation. This study not only offers a facile novel strategy to create tightly integrated spinel-layered high-performance cathode materials but also presents some new insights into the structure deterioration and the stabilization mechanism of Ni-rich layered cathode materials during charge/discharge cycles or long-term storage.

更新日期：2017-08-24

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