Improving Na<sub>2</sub>Ti<sub>3</sub>O<sub>7</sub> Anode Performance in Sodium-Ion Batteries via a Al Doping

Na<sub>2</sub>Ti<sub>3</sub>O<sub>7</sub> (NTO), with low sodium insertion potential (~0.3 V vs. Na<sup>+</sup>/Na) and potential for high-energy-density batteries, is regarded as one of the most promising anode materials for sodium-ion batteries (SIBs...

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Main Authors: Chen Wu, Yuandong Xia, Kejing Song, Yongda Cao, Chenzhi Huang, Jiayi Chen, Yuan Wang, Chunliu Xu
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Nanomaterials
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Online Access:https://www.mdpi.com/2079-4991/15/12/885
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Summary:Na<sub>2</sub>Ti<sub>3</sub>O<sub>7</sub> (NTO), with low sodium insertion potential (~0.3 V vs. Na<sup>+</sup>/Na) and potential for high-energy-density batteries, is regarded as one of the most promising anode materials for sodium-ion batteries (SIBs). However, its practical application is hindered by poor electronic conductivity, sluggish Na⁺ (de)intercalation kinetics, and interfacial instability, leading to inferior cycling stability, low initial Coulombic efficiency, and poor rate capability. In this work, micron-sized rod-like NTO and Al-doped NTO (NTO-Al) samples were synthesized via a one-step high-temperature solid-state method. Al doping slightly reduced the size of NTO microrods while introducing oxygen vacancies and generating Ti<sup>3+</sup>, thereby enhancing electronic conductivity and reducing ionic diffusion resistance. H<sub>2</sub>-TPR confirms that doping activates lattice oxygen and promotes its participation in the reaction. The optimized NTO-Al0.03 electrode delivered a significantly improved initial charge capacity of 147.4 mA h g<sup>−1</sup> at 0.5 C, surpassing pristine NTO (124.7 mA h g<sup>−1</sup>). Moreover, it exhibited the best cycling stability (49.5% capacity retention after 100 cycles) and rate performance (36.3 mA h g<sup>−1</sup> at 2 C).
ISSN:2079-4991