Na<sub>2</sub> Ti<sub>3</sub> O<sub>7</sub> @N-Doped Carbon Hollow Spheres for Sodium-Ion Batteries with Excellent Rate Performance.

Xie, Fangxi; Zhang, Lei; Su, Dawei; Jaroniec, Mietek; Qiao, Shi-Zhang · Adv Mater · 2017

basic_science · Level V

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Abstract

Uniform Na<sub>2</sub> Ti<sub>3</sub> O<sub>7</sub> hollow spheres assembled from N-doped carbon-coated ultrathin nanosheets are synthesized. A unique multilayer structure of nanosheets is presumed to significantly reduce energy consumption during the diffusion process of sodium ions, while the carbon-coated structure can increase the overall conductivity. The as-prepared sample used as an anode in sodium-ion batteries exhibits the best rate performance ever reported for Na<sub>2</sub> Ti<sub>3</sub> O<sub>7</sub> , delivering more than 60 mAh g<sup>-1</sup> after 1000 continuous cycles at the high rate of 50 C, which was achieved due to its unique structure.