Aluminium batteries constitute a safe and sustainable high‐energy‐density electrochemical energy‐storage solution. Viable Al‐ion batteries require suitable electrode materials that can readily intercalate high‐charge Al³⁺ ions. Here, we investigate the Al³⁺ intercalation chemistry of anatase TiO₂ and how chemical modifications influence the accommodation of Al³⁺ ions. We use fluoride‐ and hydroxide‐doping to generate high concentrations of titanium vacancies. The coexistence of these hetero‐anions and titanium vacancies leads to a complex insertion mechanism, attributed to three distinct types of host sites: native interstitial sites, single vacancy sites, and paired vacancy sites. We demonstrate that Al³⁺ induces a strong local distortion within the modified TiO₂ structure, which affects the insertion properties of the neighbouring host sites. Overall, specific structural features induced by the intercalation of highly polarising Al³⁺ ions should be considered when designing new electrode materials for polyvalent batteries.

中文翻译：

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电池中有缺陷的锐钛矿中铝离子插入的原子洞察。

铝电池构成了一种安全且可持续的高能量密度电化学储能解决方案。可行的Al-离子电池需要合适的电极材料，这些材料可以轻松插入高电荷的Al ³⁺离子。在这里，我们研究了锐钛矿型TiO ₂的Al ³⁺嵌入化学以及化学修饰如何影响Al ³⁺离子的容纳。我们使用氟化物和氢氧化物掺杂来产生高浓度的钛空位。这些杂阴离子和钛空位的共存导致复杂的插入机制，这归因于三种不同类型的宿主位点：天然间隙位点，单个空位位点和成对的空位位点。我们证明Al ³⁺在修饰的TiO ₂结构中引起强烈的局部变形，这会影响相邻宿主位点的插入特性。总体而言，在设计用于多价电池的新电极材料时，应考虑由高极化Al ³⁺离子的嵌入引起的特定结构特征。