Electrochemical properties of TiO2 nanotube-carbon nanotube composites as anode material of lithium-ion batteries

For use as an anode material in lithium batteries, composites consisting of TiO2 nanotubes (TNTs) and carbon nanotubes (CNTs) are prepared by combining hydrothermal reaction of rutile TiO2 bulk particles, blending with different amounts (0-30 wt.%) of CNTs, ball-milling, and subsequent heat treatment at 300 degrees C. Crystalline property analysis and morphology observation of the prepared TNT-CNT powders prove that at low CNT content the composites are consisted of dominant phase of aggregated anatase TNTs. The TNT aggregates are relaxed with increased CNT content to form crosslinked networks surrounding the amorphous CNT phases that act as a dispersing matrix. As a result, the TNT-CNT composite anode with CNT (30 wt.%) is superior for application in lithium-ion batteries because it shows a saturated discharge capacity after about 20th cycle, good high-rate capability, and the lowest interfacial resistance of 1.7-2 Omega cm(-2). The superior anode properties of TNT-CNT composite with high content of CNT are mainly due to CNT's functions to enhance electron transfer and to facilitate Li+ diffusion by dispersing the TNT agglomeration.