Tailored dealloying-driven, graphene-boosted defective rutile TiO2−x for long-term lithium storage,Materials Chemistry Frontiers

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Tailored dealloying-driven, graphene-boosted defective rutile TiO2−x for long-term lithium storage
Materials Chemistry Frontiers ( IF 6.0 ) Pub Date : 2021-2-25 , DOI: 10.1039/d1qm00188d
Yang Chen _{1,

2,

3,

4} , Zhangfeng Li _{4,

5,

6} , Chaofan Yang _{1,

2,

3,

4} , Dong Qiu _{1,

2,

3,

4} , Chengli He _{1,

2,

3,

4} , Zhiyu Jiang _{2,

3,

4,

7} , Xiaoli Cui _{1,

2,

3,

4}

Affiliation

Ti³⁺ self-doping and/or an oxygen defect-induced impurity level in TiO₂ lattices can serve as charge transfer carriers to accelerate electronic conduction, enabling TiO₂ to be a promising anode alternative in lithium-ion batteries. Although previously reported post-reduction of Ti(IV) intermediates and direct oxidation of Ti(II) precursors can be used to prepare defective rutile TiO₂, these processes usually require elevated temperatures. Herein, a tailored low-temperature dealloying approach, involving a new in situ oxidation–reduction mechanism, is proposed to synthesize blue defective rutile TiO_2−x directly. The generated air-sensitive Ti³⁺ species on the surface are then handily stabilized by coupling with graphene. As a result, the TiO_2−x/graphene composites exhibit desirable lithium storage capacities and outstanding long-term cycling stability (157 mA h g⁻¹ at 1C after 1400 cycles) owing to the [001]-axis oriented nanorod self-assembly, faster electron transfer, and improved Li⁺ diffusivity. This work highlights a new formation mechanism of defective rutile TiO_2−x, and considering the convenience and simplicity, it will provide new inspiration to the conventional dealloying strategy for low-temperature synthetic chemistry.

中文翻译：

量身定制的脱合金驱动，石墨烯增强的金红石型TiO2-x可长期储存锂

TiO ₂晶格中的Ti ³⁺自掺杂和/或氧缺陷引起的杂质水平可以用作电荷转移载体以加速电子传导，从而使TiO ₂成为锂离子电池中有希望的阳极替代品。尽管先前报道的Ti（IV）中间体的后还原反应和Ti（II）前体的直接氧化可用于制备有缺陷的金红石型TiO ₂，但这些工艺通常需要升高的温度。本文提出了一种量身定制的低温脱合金方法，该方法涉及一种新的原位氧化还原机理，用于合成蓝色缺陷的金红石型TiO _2-_x直接地。然后通过与石墨烯偶合，使表面上生成的对空气敏感的Ti ³⁺物种易于稳定。结果，由于[001]轴取向的纳米棒自组装，TiO _{2- x} /石墨烯复合材料表现出理想的锂存储容量和出色的长期循环稳定性（1400个循环后在1C下为157 mA hg ^-1）。更快的电子传输，并提高了Li ⁺扩散率。这项工作突出了一种新的有缺陷的金红石型TiO _{2- x的}形成机理，并且考虑到方便性和简便性，这将为常规的低温合成化学脱合金策略提供新的启示。

更新日期：2021-03-16

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