Hydrogenation Driven Conductive Na2Ti3O7 Nanoarrays as Robust Binder-Free Anodes for Sodium-Ion Batteries.

We present a general and rational approach to fabricate highly accessible and affordable sodium-ion battery anodes by engineering three-dimensional hydrogenated Na2Ti3O7 nanoarrays supported on flexible Ti substrates. The hydrogenated Na2Ti3O7 nanoarrays exhibit desirable properties for sodium storage, such as high surface area, high electrical conductivity, and Na(+) diffusivity. The as-obtained nanoarrays demonstrate remarkably stable and robust Na-storage performance when tested as binder-free anodes for sodium-ion battery. They can afford a high reversible (desodiation) capacity of 227 mAh g(-1) and retain a capacity of 65 mAh g(-1) over 10,000 continuous cycles at a high rate of 35 C. Therefore, through this synergy of array architecture and hydrogenation, it is possible to engineer numerous anodes that can reversibly store Na(+) ions in a fast and stable manner.