Surface Li+/Ni2+ Antisite Defects Construction for Achieving High-Voltage Stable Single-Crystal Ni-Rich Cathode by Anion/Cation Co-Doping,Advanced Functional Materials

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Surface Li+/Ni2+ Antisite Defects Construction for Achieving High-Voltage Stable Single-Crystal Ni-Rich Cathode by Anion/Cation Co-Doping
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2024-03-05 , DOI: 10.1002/adfm.202401300
Xinyou He ₁ , Jixue Shen _{1,

2} , Bao Zhang _{1,

3} , Zhiming Xiao ₁ , Long Ye ₁ , Qiuyun Mao ₁ , Qifan Zhong ₁ , Xing Ou ₁

Affiliation

Ni-rich cathode material possesses a considerable theoretical capacity, yet achieving their full capacity potential remains challenging. Elevating its operation voltage is an effective approach, while the stability of Ni-rich cathode material is relatively poor, which is limited by Li⁺/Ni²⁺ mixing. Herein, a strategy of cation/anion co-doping is proposed for single-crystal ultrahigh-nickel cathode LiNi_0.92Co_0.04Mn_0.04O₂ operated at 4.5 V. The enhancement mechanism is explicitly revealed by in situ/ex situ tests and theory calculations. Specifically, Mo⁶⁺ and F⁻ are introduced to construct an appropriate Li⁺/Ni²⁺ antisite defects structure at the particle surface, which can maintain the low-defect Li⁺ layered channel inside the bulk simultaneously, inducing a stable access portal for Li⁺ transport from the cathode/electrolyte interface. More importantly, the Li⁺/Ni²⁺ antisite passivation layer on the surface can uphold the stability of Li-layer and optimize the reactive behavior of Ni²⁺, thus boosting the interfacial stability and reducing the lattice mismatch. As a result, it can achieve high capacity (204 mAh g⁻¹ at 1 C) and stable retention during long-term high-voltage measurements both in half-cell (87.1% after 200 cycles) and full-cell (91.9% after 400 cycles). This facile strategy provides a feasible technical reference for further exploiting the ultrahigh-capacity of Ni-rich cathode for commercial application.

中文翻译：

阴离子/阳离子共掺杂实现高压稳定单晶富镍正极的表面Li+/Ni2+反位缺陷构建

富镍正极材料具有相当大的理论容量，但充分发挥其容量潜力仍然具有挑战性。提高其工作电压是一种有效的方法，但富镍正极材料的稳定性较差，这受到Li ⁺ /Ni ²⁺混合的限制。本文提出了一种针对4.5 V下工作的单晶超高镍正极LiNi _0.92 Co _0.04 Mn _0.04 O ₂的阳离子/阴离子共掺杂策略。通过原位/异位测试和理论计算明确揭示了增强机制。。具体来说，引入Mo ⁶⁺和F ^-在颗粒表面构建适当的Li ⁺ /Ni ²⁺反位缺陷结构，可以同时维持块体内部的低缺陷Li ⁺层状通道，从而为材料提供稳定的入口。 Li ⁺从阴极/电解质界面传输。更重要的是，表面的Li ⁺ /Ni ²⁺反位钝化层可以维持Li层的稳定性并优化Ni ²⁺的反应行为，从而提高界面稳定性并减少晶格失配。因此，它可以在半电池（200次循环后为87.1%）和全电池（200次循环后为91.9%）中实现高容量（204 mAh g ^-1 at 1 C）和长期高电压测量过程中的稳定保留。 400 个周期）。这种简便的策略为进一步开发超高容量富镍正极的商业应用提供了可行的技术参考。

更新日期：2024-03-05

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