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

Three-dimensional (3D) titanium dioxide@germanium (TiO2@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 TiO2@Ge composite involves the hydrothermal growth of TiO2 nanorod arrays on carbon textiles and a subsequent coat with a thin layer of germanium with radio frequency (RF) magnetron sputtering. The TiO2 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 TiO2 can be in situ lithiated to LixTiO2 after the first discharge cycle. Moreover, each TiO2@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). [ABSTRACT FROM AUTHOR]