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 4 & Scy;, 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.