Hierarchical nanocomposite based on Na2Ti3O7 and Fe2O3 for electrochemical sodium ion storage: Preparation and characterization

A key task nowadays is the development of novel materials and the enhancement of known ones in order to design high-performance anodes for sodium-ion batteries. This article presents a one-pot method of preparing a nanocomposite with hierarchical structure based on sodium trititanate and iron(III) oxide. In this method, simultaneous hydrothermal treatment of TiO₂ and FeCl₃ in a concentrated NaOH solution results in the formation of microscale particles self-assembled of Na₂Ti₃O₇ nanotubes and Fe₂O₃ nanospheres. A Na₂Ti₃O₇–Fe₂O₃ nanocomposite is being investigated for the first time as a potential anode material for sodium-ion batteries. It was found that combining Na₂Ti₃O₇ with Fe₂O₃ as a high-capacitive modifier within the hierarchical structure improves Na-ion storage performance. Its specific capacity reaches about 220 and 50 mAh g⁻¹ at 0.1C and 4С, respectively. The pure Na₂Ti₃O₇ gives only around 145 and 10 mAh g⁻¹ at the same current densities. Besides, the Na₂Ti₃O₇–Fe₂O₃ nanocomposite operates stably during 1000 charge/discharge cycles at a rate of 2C with a reversible capacity of 90 mAh g⁻¹, whereas both pure Na₂Ti₃O₇ and Fe₂O₃ exhibit worse long-term performance. These findings improve our knowledge of how to combine different materials in order to enhance their functionalities for application as an anode in sodium-ion batteries.