In contrast to monovalent lithium or sodium ions, the reversible insertion of multivalent ions such as Mg²⁺ and Al³⁺ into electrode materials remains an elusive goal. Here, we demonstrate a new strategy to achieve reversible Mg²⁺ and Al³⁺ insertion in anatase TiO₂, achieved through aliovalent doping, to introduce a large number of titanium vacancies that act as intercalation sites. We present a broad range of experimental and theoretical characterizations that show a preferential insertion of multivalent ions into titanium vacancies, allowing a much greater capacity to be obtained compared to pure TiO₂. This result highlights the possibility to use the chemistry of defects to unlock the electrochemical activity of known materials, providing a new strategy for the chemical design of materials for practical multivalent batteries.

与单价锂或钠离子相反，将多价离子（例如Mg ²⁺和Al ^3+）可逆地插入电极材料仍然是一个遥不可及的目标。在这里，我们展示了一种新的策略，可通过异价掺杂实现在锐钛矿型TiO _2中实现可逆的Mg ²⁺和Al ³⁺插入，从而引入大量的钛空位作为嵌入位。我们提供了广泛的实验和理论特征，这些特征表明多价离子优先插入钛空位中，与纯TiO ₂相比，可以获得更大的容量。该结果突出显示了利用缺陷的化学性质来释放已知材料的电化学活性的可能性，从而为用于实际的多价电池的材料的化学设计提供了新的策略。