In the present study, Al₂O₃ is utilized for the first time as coating agent on nanostructured anatase TiO₂ in order to investigate its effect on sodium-ion batteries performance. Our results show that the Al₂O₃ coating, introduced by a facile two-step approach, provides beneficial effects to the TiO₂-based anodes. However, the coated TiO₂ still suffers of capacity fading upon cycling when using 1.0 M of NaClO₄ in propylene carbonate (PC) as electrolyte. To address this issue, the influence of different electrolytes (NaClO₄ salt in various solvents) is further studied. It is found that the modified TiO₂ exhibits significant improvements in cycling performance using binary ethylene carbonate (EC) and PC solvent mixture without the need of the commonly used fluoroethylene carbonate (FEC) additive. Under the best configuration, our battery could deliver a high reversible capacity of 188.1 mAh g⁻¹ at 0.1C after 50 cycles, good rate capability up to 5C, and remarkable long-term cycling stability at 1C rate for 650 cycles. This excellent performance can be ascribed to the synergistic effects of surface and interface engineering enabling the formation of a stable and highly ionic conductive interface layer in EC:PC based electrolyte which combines the native SEI film and an ‘artificial’ SEI layer of irreversibly formed Na−Al−O.

在本研究中，Al ₂ O ₃首次用作纳米结构锐钛矿型TiO _2的涂层剂，以研究其对钠离子电池性能的影响。我们的结果表明，通过简便的两步法引入的Al ₂ O ₃涂层为TiO ₂基阳极提供了有益的作用。然而，当在碳酸亚丙酯（PC）中使用1.0M的NaClO ₄时，涂覆的TiO ₂在循环时仍遭受容量衰减的影响。为了解决这个问题，进一步研究了不同电解质（各种溶剂中的NaClO ₄盐）的影响。发现改性TiO_图2显示了使用二元碳酸亚乙酯（EC）和PC溶剂混合物的循环性能的显着改善，而无需通常使用的氟代碳酸亚乙酯（FEC）添加剂。在最佳配置下，我们的电池可 在50次循环后在0.1C下提供188.1 mAh g ^-1的高可逆容量，高达5C的良好倍率能力以及在650个循环下以1C倍率具有出色的长期循环稳定性。这种优异的性能可归因于表面和界面工程的协同效应，可在基于EC：PC的电解质中形成稳定且高度离子化的导电界面层，该界面结合了天然SEI膜和不可逆形成的Na的“人工” SEI层-Al-O。