Ultrafast sodium storage in anatase TiO2 nanoparticles embedded on carbon nanotubes

By Jang‐Yeon Hwang, Seung‐Taek Myung, J. Lee, A. Abouimrane, I. Belharouak, Yang‐Kook Sun. 2015

141 citations recorded by the source corpus.

Abstract The main disadvantage of using transition metal oxides for Na + -ion batteries is the sluggish kinetics of insertion of Na + ions into the structure. Here, we introduce nanosized anatase TiO 2 that is partially doped with fluorine (TiO 2− δ F δ ) to form electro-conducting trivalent Ti 3+ as an ultrafast Na + insertion material for use as an anode for sodium-ion batteries. In addition, the F-doped TiO 2− δ F δ is modified by electro-conducting carbon nanotubes (CNTs) to further enhance the electric conductivity. The composite F-doped TiO 2 embedded in CNTs is produced in a one-pot hydrothermal reaction. X-ray diffraction and microscopic studies revealed that nanocrystalline anatase-type TiO 2− δ F δ particles, in which fluorine is present with TiO 2 particles, are loaded on the CNTs. This yields a high electric conductivity of approximately 5.8 S cm −1 . The first discharge capacity of the F-doped TiO 2 embedded in CNTs is approximately 250 mA h (g-oxide) −1 , and is retained at 97% after 100 cycles. As expected, a high-rate performance was achieved even at the 100 C discharging rate (25 A g −1 ) where the composite material demonstrated a capacity of 118 mA h g −1 under the 0.1 C-rate charge condition. The present work also highlights a significant improvement in the insertion and extraction of Na + ions when the material was charged and discharged under the same rate of 35 C (8.75 A g −1 ), delivering approximately 90 mA h (g-oxide) −1 .

Subfields: Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/daebe4785d291e47832eea753b4a640efef7158b