Titanium Dioxide/Germanium Core–Shell Nanorod Arrays Grown on Carbon Textiles as Flexible Electrodes for High Density Lithium‐Ion Batteries

Abstract

Three‐dimensional (3D) titanium dioxide@germanium (TiO 2 @Ge) core–shell nanorod arrays on carbon textiles are fabricated by a facile two‐step method and further investigated as flexible electrode for Li‐ion batteries (LIBs). The synthesis of TiO 2 @Ge composite involves the hydrothermal growth of TiO 2 nanorod arrays on carbon textiles and a subsequent coat with a thin layer of germanium with radio frequency (RF) magnetron sputtering. The TiO 2 nanorod arrays can effectively not only increase the unit mass loading as a role of skeleton but also remarkably enhance the electrical conductivity via control the lithiation/delithiation voltage in the range of 0.01–1.0 V, where TiO 2 can be in situ lithiated to Li x TiO 2 after the first discharge cycle. Moreover, each TiO 2 @Ge nanorod has enough space to accommodate the large volume expansion of Ge during charge and discharge cycles. Benefiting from unique electrode architectures, this additive free, self‐supported electrode exhibits the high reversible capacity, outstanding rate capability, and the extremely long cycling stability even at a high rate (700.3 mAh g −1 is still retained at 5 A g −1 after 600 cycles).