Exploring the Effect of Cation Vacancies in TiO2: Lithiation Behavior of n-Type and p-Type TiO2,ACS Applied Materials & Interfaces

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Exploring the Effect of Cation Vacancies in TiO2: Lithiation Behavior of n-Type and p-Type TiO2
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2022-01-28 , DOI: 10.1021/acsami.1c20265
Moo Dong Lee ₁ , Geun Jun Lee ₁ , Inho Nam ₂ , Muhammad A Abbas ₃ , Jin Ho Bang _{3,

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Affiliation

TiO₂ offers several advantages over graphite as an anode material for Li-ion batteries (LIBs) but suffers from low electrical conductivity and Li-diffusion issues. Control over defect chemistry has proven to be an effective strategy to overcome these issues. However, defect engineering has primarily been focused on oxygen vacancies (V_O). The role of another intrinsic TiO₂ vacancy [i.e., titanium vacancies (V_Ti)] with regard to the Li⁺ storage behavior of TiO₂ has largely evaded attention. Hence, a comparison of V_O- and V_Ti-defective TiO₂ can provide valuable insight into how these two types of defects affect Li⁺ storage behavior. To eliminate other factors that may also affect the Li⁺ storage behavior of TiO₂, we carefully devised synthesis protocols to prepare TiO₂ with either V_O (n-TiO₂) or V_Ti (p-TiO₂). Both TiO₂ materials were verified to have a very similar morphology, surface area, and crystal structure. Although V_O provided additional sites that improved the capacity at low C-rates, the benefit obtained from over-lithiation turned out to be detrimental to cycling stability. Unlike V_O, V_Ti could not serve as an additional lithium reservoir but could significantly improve the rate performance of TiO₂. More importantly, the presence of V_Ti prevented over-lithiation, significantly improving the cycling stability of TiO₂. We believe that these new insights could help guide the development of high-performance TiO₂ for LIB applications.

中文翻译：

探索 TiO2 中阳离子空位的影响：n 型和 p 型 TiO2 的锂化行为

与石墨相比， TiO ₂作为锂离子电池 (LIB) 的负极材料具有多种优势，但存在低电导率和锂扩散问题。控制缺陷化学已被证明是克服这些问题的有效策略。然而，缺陷工程主要集中在氧空位（VO _）上。另一个固有的TiO ₂空位[即钛空位(V _{Ti )]对于TiO}₂的Li ⁺存储行为的作用已经很大程度上回避了关注。因此，V _O - 和 V _Ti -缺陷型 TiO _2的比较^{可以为这两种类型的缺陷如何影响 Li +}存储行为提供有价值的见解。_{为了消除也可能影响 TiO 2的 Li}⁺存储行为的其他因素，我们仔细设计了合成方案来制备具有 V _O (n-TiO ₂ ) 或 V _Ti (p-TiO _{2 ) 的 TiO}₂。两种TiO ₂材料经证实具有非常相似的形态、表面积和晶体结构。尽管 V _O提供了额外的位点，从而提高了低 C 率下的容量，但从过度锂化中获得的好处被证明不利于循环稳定性。_不像VO, V _Ti不能作为额外的锂储层，但可以显着提高 TiO ₂的倍率性能。更重要的是，V _Ti的存在防止了过度锂化，显着提高了 TiO ₂的循环稳定性。我们相信，这些新见解可以帮助指导用于 LIB 应用的高性能 TiO _{2的开发。}

更新日期：2022-02-09

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