Anode properties of titanium oxide nanotube and graphite composites for lithium-ion batteries

摘要

Titanium oxide nanotube and graphite composites are prepared by adding graphite before and after a hydrothermal reaction to enhance the cyclic performance and high-rate capability of lithium-ion batteries. The composite powders, their anode electrodes, and lithium half-cells containing the anodes are characterized by means of morphological and crystalline analysis, Raman spectroscopy, cyclic voltamme-try, impedance spectroscopy, and repeated discharge-charge cycling at low and high C-rates. Notably, the composite anode (R5G5-T) that concurrently uses natural graphite and rutile particles before the hydrothermal reaction shows superior high-rate capability and achieves a discharge capacity of ca. 70mAh g~(-1) after 100 cycles at 50C-rate. This may be due to the high-rate supercapacitive reactions of the TiO_2 nanotube on the graphite surface caused by a diffusion-controlled or a charge-transfer process.