Aluminum intercalation and transport in TiO2(B) from first principles

Abstract

Abstract Aluminum-ion batteries have emerged as a potential alternative to lithium-ion batteries by offering advantages such as abundant aluminum resources, low costs and good safety. Exploring suitable electrode materials lies at the heart of the development of aluminum-ion batteries. Relying on first-principles density functional theory, this study predicts the thermodynamics of aluminum intercalation in TiO 2 (B) as a promising aluminum storage material. Three sites are identified to be the preferential locations for aluminum within the TiO 2 (B) structure, and the stable intercalation site is found to prefer 5-fold coordinated to oxygen atoms with a slightly off-center position. The supercell volume change associated with aluminum intercalation is −1 and 755.05 mA h g −1 , doubling the theoretical value of lithium storage in TiO 2 (B). As expected, aluminum has a very poor mobility in bulk TiO 2 (B) due to its exceptionally high surface charge density, which would be addressable through the use of nanosized and defective materials. Our calculations suggest that TiO 2 (B) can offer new opportunities for developing electrode materials for aluminum-ion batteries.