3D flower-like NaHTi₃O₇ nanotubes as high-performance anodes for sodium-ion batteries

The synthesis and electrochemical performance derived from NaHTi₃O₇ have been investigated for use as an anode material for sodium-ion batteries. NaHTi₃O₇ nanotubes were fabricated by a hydrothermal method. Galvanostatic charge/discharge measurements were performed in a voltage range of 0.01-2.5 V vs. Na⁺/Na at different current densities, using the as-prepared NaHTi₃O₇ nanotubes as the working electrode. Typically, the initial discharge and charge capacities of NaHTi₃O₇ nanotubes were 381.80 mA h g^-1 and 242.82 mA h g^-1, respectively, at a current density of 20 mA g^-1, and still retained a high specific capacity of 105.32 mA h g^-1 and 100.65 mA h g^-1 after 100 cycles. The electrode also exhibits outstanding rate capability with a reversible capacity as high as 300.95 mA h g^-1 and 209.10 mA h g^-1 at current densities of 50 mA g^-1 and 100 mA g^-1, respectively. The excellent electrochemical stability and high specific capacity of these nanostructured materials have been attributed to the three-dimensional flower-like morphology of NaHTi₃O₇ nanotubes. All of the findings demonstrate that NaHTi₃O₇ nanotubes have steady cycling performance and environmental and cost friendliness for use in next generation secondary batteries of sodium-ion batteries.