Na₂Ti₃O₇/C Nanofibers for High-Rate and Ultralong-Life Anodes in Sodium-Ion Batteries

Na₂Ti₃O₇/C nanofibers are successfully synthesized through an electrospinning process followed by hydrothermal treatment. The unique structure of these one-dimensional nanofibers with two-dimensional nanosheets on the surface is presumed to significantly shorten the diffusion routes for both electrons and ions. Meanwhile, the carbon matrix with a certain degree of graphitization can dramatically improve the overall conductivity. As a result, the Na₂Ti₃O₇/C nanofiber electrode reveals an impressive electrochemical capability as the anode material of sodium-ion batteries. It demonstrates a reversible capacity of 110 mA h g⁻¹ after 500 cycles at a rate of 1 C. Moreover, with almost no capacity degradation, the discharge capacity of the Na₂Ti₃O₇/C nanofiber electrode remains at 58 mA h g⁻¹ after 1500 cycles at the high rate of 50 C. This superior electrochemical performance places the Na₂Ti₃O₇/C nanofibers as an anode material with great promise for sodium-ion batteries that could be applied in large-scale energy storage.