The aqueous battery employing multivalent metal ions as charge carriers is theoretically a high energy density electrochemical energy storage device due to the fact that it carries more charges. However, the storage mechanism of multivalent metal ions, especially Al³⁺ ions, in TiO₂ materials has not been established.

A new model associated with the contribution of multivalent metal ions, water molecules and protons in the charging/discharging process of the electrode is established in this work. The storage mechanism of aqueous Al³⁺ ion batteries is revealed from a new perspective by studying the relationship between the charge inside the TiO₂ film and the mass at the interface. More importantly, a highlighted work is to reveal the changes in the amount of interfacial free water molecules and the hydration number of Al³⁺ ions due to the adsorption/desorption of hydrated ions during the charging/discharging process.

The present work is of great significance for revealing the mechanism of multivalent cations on metal oxide surfaces in aqueous batteries, and meanwhile, the model established can also be extended to other fields such as supercapacitors, photovoltaics, and photocatalysis. The results obtained in this work may have an impact on the performance of energy storage batteries, especially the influence of the rearrangement of interface hydration ions and water molecules on the energy storage mechanism.

以多价金属离子为电荷载体的水系电池由于携带更多电荷，理论上是一种高能量密度的电化学储能装置。然而，多价金属离子，尤其是Al ³⁺离子在TiO ₂材料中的存储机制尚未确定。

这项工作建立了一个与多价金属离子、水分子和质子在电极充电/放电过程中的贡献相关的新模型。_{通过研究TiO 2}薄膜内部电荷与界面质量之间的关系，从新的角度揭示了水系Al ^{3+离子电池的存储机制。}更重要的是，一个突出的工作是揭示了在充电/放电过程中由于水合离子的吸附/解吸而导致的界面游离水分子数量和Al ^{3+离子水合数的变化。}

目前的工作对于揭示水系电池中金属氧化物表面多价阳离子的作用机理具有重要意义，同时所建立的模型还可以推广到超级电容器、光伏、光催化等其他领域。本工作获得的结果可能对储能电池的性能产生影响，尤其是界面水合离子和水分子重排对储能机制的影响。